From 5539dbe620f3a184490010a706104de36ba80c3e Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
Date: Wed, 29 Sep 2021 08:45:13 +0200
Subject: [PATCH] Add separate serialize feature and better persitence control
 (#753)

* Rename epaint feature "persistence" to "serialize"

* Add separate "serialize" feature to egui

* egui_demo_lib: separate serialize and persistence features

* Add App::persist_native_window and App::persist_egui_memory

Controls what gets persisted
---
 CHANGELOG.md                                  |  3 +-
 eframe/CHANGELOG.md                           |  3 +-
 egui/Cargo.toml                               | 10 ++++--
 egui/src/any/serializable/type_id.rs          |  2 +-
 egui/src/containers/area.rs                   |  2 +-
 egui/src/containers/collapsing_header.rs      |  4 +--
 egui/src/containers/panel.rs                  |  2 +-
 egui/src/containers/resize.rs                 |  2 +-
 egui/src/containers/scroll_area.rs            |  6 ++--
 egui/src/data/input.rs                        | 20 ++++++------
 egui/src/data/output.rs                       | 10 +++---
 egui/src/grid.rs                              |  2 +-
 egui/src/id.rs                                |  2 +-
 egui/src/layers.rs                            |  4 +--
 egui/src/layout.rs                            |  6 ++--
 egui/src/lib.rs                               |  2 +-
 egui/src/memory.rs                            | 24 +++++++-------
 egui/src/menu.rs                              |  4 +--
 egui/src/sense.rs                             |  2 +-
 egui/src/style.rs                             | 28 ++++++++--------
 egui/src/util/undoer.rs                       |  6 ++--
 egui/src/widgets/plot/mod.rs                  |  2 +-
 egui/src/widgets/plot/transform.rs            |  2 +-
 egui/src/widgets/text_edit.rs                 | 14 ++++----
 egui_demo_lib/Cargo.toml                      |  8 +++--
 egui_demo_lib/src/apps/color_test.rs          |  4 +--
 egui_demo_lib/src/apps/demo/app.rs            | 10 +++---
 egui_demo_lib/src/apps/demo/code_editor.rs    |  6 ++--
 .../src/apps/demo/dancing_strings.rs          |  4 +--
 .../src/apps/demo/demo_app_windows.rs         | 16 +++++-----
 egui_demo_lib/src/apps/demo/layout_test.rs    |  8 ++---
 .../src/apps/demo/misc_demo_window.rs         | 20 ++++++------
 egui_demo_lib/src/apps/demo/painting.rs       |  4 +--
 egui_demo_lib/src/apps/demo/scrolling.rs      | 10 +++---
 egui_demo_lib/src/apps/demo/sliders.rs        |  4 +--
 egui_demo_lib/src/apps/demo/tests.rs          |  2 +-
 egui_demo_lib/src/apps/demo/widget_gallery.rs |  4 +--
 egui_demo_lib/src/apps/demo/window_options.rs |  2 +-
 .../src/apps/demo/window_with_panels.rs       |  2 +-
 egui_demo_lib/src/apps/fractal_clock.rs       |  4 +--
 egui_demo_lib/src/apps/http_app.rs            | 10 +++---
 egui_demo_lib/src/backend_panel.rs            | 12 +++----
 .../src/easy_mark/easy_mark_editor.rs         |  6 ++--
 egui_demo_lib/src/wrap_app.rs                 | 15 ++++-----
 egui_glium/src/backend.rs                     | 32 ++++++++++++-------
 egui_web/src/backend.rs                       |  4 ++-
 epaint/Cargo.toml                             |  3 +-
 epaint/src/color.rs                           |  4 +--
 epaint/src/lib.rs                             |  4 +--
 epaint/src/mesh.rs                            |  4 +--
 epaint/src/shadow.rs                          |  2 +-
 epaint/src/shape.rs                           |  6 ++--
 epaint/src/stroke.rs                          |  2 +-
 epaint/src/tessellator.rs                     |  4 +--
 epaint/src/text/cursor.rs                     |  8 ++---
 epaint/src/text/fonts.rs                      | 12 +++----
 epaint/src/text/text_layout_types.rs          |  6 ++--
 epi/src/lib.rs                                | 16 +++++++++-
 58 files changed, 226 insertions(+), 194 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 90839285..c3f7d0bc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,13 +11,14 @@ NOTE: [`eframe`](eframe/CHANGELOG.md), [`egui_web`](egui_web/CHANGELOG.md), [`eg
 * Add horizontal scrolling support to `ScrollArea` and `Window` (opt-in).
 * `TextEdit::layouter`: Add custom text layout for e.g. syntax highlighting or WYSIWYG.
 * `Fonts::layout_job*`: New text layout engine allowing mixing fonts, colors and styles, with underlining and strikethrough.
+* Add feature `"serialize"` separatedly from `"persistence"`.
 
 ### Changed 🔧
 * Label text will now be centered, right-aligned and/or justified based on the layout.
 * `Hyperlink` will now word-wrap just like a `Label`.
 * All `Ui`:s must now have a finite `max_rect`.
   * Deprecated: `max_rect_finite`, `available_size_before_wrap_finite` and `available_rect_before_wrap_finite`.
-* `Painter`/`Fonts`: text layout now expect color when creating a `Galley`. You may override that color with `Painter::galley_with_color`.
+* `Painter`/`Fonts`: text layout now expect a color when creating a `Galley`. You may override that color with `Painter::galley_with_color`.
 * MSRV (Minimum Supported Rust Version) is now `1.54.0`.
 * By default, `DragValue`:s no longer show a tooltip when hovered. Change with `Style::explanation_tooltips`.
 
diff --git a/eframe/CHANGELOG.md b/eframe/CHANGELOG.md
index 629b523a..8d870e29 100644
--- a/eframe/CHANGELOG.md
+++ b/eframe/CHANGELOG.md
@@ -1,11 +1,12 @@
 # Changelog for eframe
-All notable changes to the `eframe` crate.
+All notable changes to the `eframe` and `epi` crates.
 
 
 ## Unreleased
 * `Frame` now provides `set_decorations` to set whether to show window decorations.
 * Remove "http" feature (use https://github.com/emilk/ehttp instead!).
 * Increase native scroll speed.
+* Add `App::persist_native_window` and `App::persist_egui_memory` to control what gets persisted.
 
 
 ## 0.14.0 - 2021-08-24
diff --git a/egui/Cargo.toml b/egui/Cargo.toml
index d1582acf..499f51de 100644
--- a/egui/Cargo.toml
+++ b/egui/Cargo.toml
@@ -30,6 +30,9 @@ ron = { version = "0.6.4", optional = true }
 [features]
 default = ["default_fonts", "single_threaded"]
 
+# add compatibility with https://crates.io/crates/cint
+cint = ["epaint/cint"]
+
 # If set, egui will use `include_bytes!` to bundle some fonts.
 # If you plan on specifying your own fonts you may disable this feature.
 default_fonts = ["epaint/default_fonts"]
@@ -42,10 +45,11 @@ extra_asserts = ["epaint/extra_asserts"]
 # Add compatability with https://github.com/kvark/mint
 mint = ["epaint/mint"]
 
-# add compatibility with https://crates.io/crates/cint
-cint = ["epaint/cint"]
+# enable persistence of memory (window positions etc).
+persistence = ["serde", "epaint/serialize", "ron"]
 
-persistence = ["serde", "epaint/persistence", "ron"]
+# implement serde on most types.
+serialize = ["serde", "epaint/serialize"]
 
 # multi_threaded is only needed if you plan to use the same egui::Context
 # from multiple threads. It comes with a minor performance impact.
diff --git a/egui/src/any/serializable/type_id.rs b/egui/src/any/serializable/type_id.rs
index abc377c1..414670ff 100644
--- a/egui/src/any/serializable/type_id.rs
+++ b/egui/src/any/serializable/type_id.rs
@@ -2,7 +2,7 @@ use std::any::Any;
 
 /// We need this because `TypeId` can't be deserialized or serialized directly, but this can be done using hashing. However, there is a small possibility that different types will have intersection by hashes of their type ids.
 #[derive(Clone, Copy, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct TypeId(u64);
 
 impl TypeId {
diff --git a/egui/src/containers/area.rs b/egui/src/containers/area.rs
index e55b9124..ec91371d 100644
--- a/egui/src/containers/area.rs
+++ b/egui/src/containers/area.rs
@@ -8,7 +8,7 @@ use crate::*;
 
 /// State that is persisted between frames
 #[derive(Clone, Copy, Debug)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub(crate) struct State {
     /// Last known pos
     pub pos: Pos2,
diff --git a/egui/src/containers/collapsing_header.rs b/egui/src/containers/collapsing_header.rs
index 448349e1..18922fbd 100644
--- a/egui/src/containers/collapsing_header.rs
+++ b/egui/src/containers/collapsing_header.rs
@@ -4,8 +4,8 @@ use crate::{widgets::Label, *};
 use epaint::{Shape, TextStyle};
 
 #[derive(Clone, Copy, Debug)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub(crate) struct State {
     open: bool,
 
diff --git a/egui/src/containers/panel.rs b/egui/src/containers/panel.rs
index 6bf72de8..5cab86db 100644
--- a/egui/src/containers/panel.rs
+++ b/egui/src/containers/panel.rs
@@ -18,7 +18,7 @@ use std::ops::RangeInclusive;
 use crate::*;
 
 #[derive(Clone, Copy, Debug)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 struct PanelState {
     rect: Rect,
 }
diff --git a/egui/src/containers/resize.rs b/egui/src/containers/resize.rs
index 92d9436c..03069eb0 100644
--- a/egui/src/containers/resize.rs
+++ b/egui/src/containers/resize.rs
@@ -1,7 +1,7 @@
 use crate::*;
 
 #[derive(Clone, Copy, Debug)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub(crate) struct State {
     /// This is the size that the user has picked by dragging the resize handles.
     /// This may be smaller and/or larger than the actual size.
diff --git a/egui/src/containers/scroll_area.rs b/egui/src/containers/scroll_area.rs
index a4dfdfbd..39dd1de9 100644
--- a/egui/src/containers/scroll_area.rs
+++ b/egui/src/containers/scroll_area.rs
@@ -8,8 +8,8 @@
 use crate::*;
 
 #[derive(Clone, Copy, Debug)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub(crate) struct State {
     /// Positive offset means scrolling down/right
     offset: Vec2,
@@ -17,7 +17,7 @@ pub(crate) struct State {
     show_scroll: [bool; 2],
 
     /// Momentum, used for kinetic scrolling
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     pub vel: Vec2,
 
     /// Mouse offset relative to the top of the handle when started moving the handle.
diff --git a/egui/src/data/input.rs b/egui/src/data/input.rs
index 69ab6752..07ebfd38 100644
--- a/egui/src/data/input.rs
+++ b/egui/src/data/input.rs
@@ -11,7 +11,7 @@ use crate::emath::*;
 ///
 /// All coordinates are in points (logical pixels) with origin (0, 0) in the top left corner.
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct RawInput {
     /// How many points (logical pixels) the user scrolled
     pub scroll_delta: Vec2,
@@ -132,7 +132,7 @@ impl RawInput {
 
 /// A file about to be dropped into egui.
 #[derive(Clone, Debug, Default, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct HoveredFile {
     /// Set by the `egui-winit` backend.
     pub path: Option<std::path::PathBuf>,
@@ -142,7 +142,7 @@ pub struct HoveredFile {
 
 /// A file dropped into egui.
 #[derive(Clone, Debug, Default, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct DroppedFile {
     /// Set by the `egui-winit` backend.
     pub path: Option<std::path::PathBuf>,
@@ -158,7 +158,7 @@ pub struct DroppedFile {
 ///
 /// This only covers events that egui cares about.
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub enum Event {
     /// The integration detected a "copy" event (e.g. Cmd+C).
     Copy,
@@ -217,7 +217,7 @@ pub enum Event {
 
 /// Mouse button (or similar for touch input)
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub enum PointerButton {
     /// The primary mouse button is usually the left one.
     Primary = 0,
@@ -233,7 +233,7 @@ pub const NUM_POINTER_BUTTONS: usize = 3;
 
 /// State of the modifier keys. These must be fed to egui.
 #[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Modifiers {
     /// Either of the alt keys are down (option ⌥ on Mac).
     pub alt: bool,
@@ -276,7 +276,7 @@ impl Modifiers {
 /// Many keys are omitted because they are not always physical keys (depending on keyboard language), e.g. `;` and `§`,
 /// and are therefor unsuitable as keyboard shortcuts if you want your app to be portable.
 #[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd, Hash)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub enum Key {
     ArrowDown,
     ArrowLeft,
@@ -383,19 +383,19 @@ impl RawInput {
 
 /// this is a `u64` as values of this kind can always be obtained by hashing
 #[derive(Clone, Copy, Debug, Eq, PartialEq, PartialOrd, Ord)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct TouchDeviceId(pub u64);
 
 /// Unique identification of a touch occurrence (finger or pen or ...).
 /// A Touch ID is valid until the finger is lifted.
 /// A new ID is used for the next touch.
 #[derive(Clone, Copy, Debug, Eq, PartialEq, PartialOrd, Ord)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct TouchId(pub u64);
 
 /// In what phase a touch event is in.
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub enum TouchPhase {
     /// User just placed a touch point on the touch surface
     Start,
diff --git a/egui/src/data/output.rs b/egui/src/data/output.rs
index e3b1d0ec..0ec1a319 100644
--- a/egui/src/data/output.rs
+++ b/egui/src/data/output.rs
@@ -5,7 +5,7 @@ use crate::WidgetType;
 /// What egui emits each frame.
 /// The backend should use this.
 #[derive(Clone, Default, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Output {
     /// Set the cursor to this icon.
     pub cursor_icon: CursorIcon,
@@ -89,7 +89,7 @@ impl Output {
 }
 
 #[derive(Clone, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct OpenUrl {
     pub url: String,
     /// If `true`, open the url in a new tab.
@@ -122,7 +122,7 @@ impl OpenUrl {
 ///
 /// Loosely based on <https://developer.mozilla.org/en-US/docs/Web/CSS/cursor>.
 #[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub enum CursorIcon {
     /// Normal cursor icon, whatever that is.
     Default,
@@ -244,7 +244,7 @@ impl Default for CursorIcon {
 ///
 /// In particular, these events may be useful for accessability, i.e. for screen readers.
 #[derive(Clone, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub enum OutputEvent {
     // A widget was clicked.
     Clicked(WidgetInfo),
@@ -272,7 +272,7 @@ impl std::fmt::Debug for OutputEvent {
 
 /// Describes a widget such as a [`crate::Button`] or a [`crate::TextEdit`].
 #[derive(Clone, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct WidgetInfo {
     /// The type of widget this is.
     pub typ: WidgetType,
diff --git a/egui/src/grid.rs b/egui/src/grid.rs
index b8489f04..7ad6943e 100644
--- a/egui/src/grid.rs
+++ b/egui/src/grid.rs
@@ -1,7 +1,7 @@
 use crate::*;
 
 #[derive(Clone, Debug, Default, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub(crate) struct State {
     col_widths: Vec<f32>,
     row_heights: Vec<f32>,
diff --git a/egui/src/id.rs b/egui/src/id.rs
index 5e4367bb..407b8101 100644
--- a/egui/src/id.rs
+++ b/egui/src/id.rs
@@ -26,7 +26,7 @@
 /// Then there are widgets that need no identifiers at all, like labels,
 /// because they have no state nor are interacted with.
 #[derive(Clone, Copy, Hash, Eq, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Id(u64);
 
 impl Id {
diff --git a/egui/src/layers.rs b/egui/src/layers.rs
index 7ba1ff66..a0e44ccc 100644
--- a/egui/src/layers.rs
+++ b/egui/src/layers.rs
@@ -9,7 +9,7 @@ use std::sync::Arc;
 
 /// Different layer categories
 #[derive(Clone, Copy, Debug, Hash, Eq, PartialEq, Ord, PartialOrd)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub enum Order {
     /// Painted behind all floating windows
     Background,
@@ -65,7 +65,7 @@ impl Order {
 /// An identifier for a paint layer.
 /// Also acts as an identifier for [`Area`]:s.
 #[derive(Clone, Copy, Debug, Hash, Eq, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct LayerId {
     pub order: Order,
     pub id: Id,
diff --git a/egui/src/layout.rs b/egui/src/layout.rs
index fafc8b2e..3678d392 100644
--- a/egui/src/layout.rs
+++ b/egui/src/layout.rs
@@ -76,8 +76,8 @@ impl Region {
 
 /// Layout direction, one of `LeftToRight`, `RightToLeft`, `TopDown`, `BottomUp`.
 #[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(rename_all = "snake_case"))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(rename_all = "snake_case"))]
 pub enum Direction {
     LeftToRight,
     RightToLeft,
@@ -115,7 +115,7 @@ impl Direction {
 /// });
 /// ```
 #[derive(Clone, Copy, Debug, PartialEq)]
-// #[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+// #[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Layout {
     /// Main axis direction
     main_dir: Direction,
diff --git a/egui/src/lib.rs b/egui/src/lib.rs
index 7d05f0e0..3b6e1fa8 100644
--- a/egui/src/lib.rs
+++ b/egui/src/lib.rs
@@ -527,7 +527,7 @@ pub mod special_emojis {
 
 /// The different types of built-in widgets in egui
 #[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub enum WidgetType {
     Label, // TODO: emit Label events
     Hyperlink,
diff --git a/egui/src/memory.rs b/egui/src/memory.rs
index 3bbbedb1..ea0052c3 100644
--- a/egui/src/memory.rs
+++ b/egui/src/memory.rs
@@ -14,8 +14,8 @@ use crate::{any, area, window, Id, InputState, LayerId, Pos2, Rect, Style};
 /// If you want to store data for your widgets, you should look at `data`/`data_temp` and
 /// `id_data`/`id_data_temp` fields, and read the documentation of [`any`] module.
 #[derive(Clone, Debug, Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct Memory {
     pub options: Options,
 
@@ -53,23 +53,23 @@ pub struct Memory {
     /// new fonts that will be applied at the start of the next frame
     pub(crate) new_font_definitions: Option<epaint::text::FontDefinitions>,
 
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     pub(crate) interaction: Interaction,
 
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     pub(crate) window_interaction: Option<window::WindowInteraction>,
 
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     pub(crate) drag_value: crate::widgets::drag_value::MonoState,
 
     pub(crate) areas: Areas,
 
     /// Which popup-window is open (if any)?
     /// Could be a combo box, color picker, menu etc.
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     popup: Option<Id>,
 
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     everything_is_visible: bool,
 }
 
@@ -77,11 +77,11 @@ pub struct Memory {
 
 /// Some global options that you can read and write.
 #[derive(Clone, Debug, Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct Options {
     /// The default style for new `Ui`:s.
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     pub(crate) style: std::sync::Arc<Style>,
 
     /// Controls the tessellator.
@@ -432,8 +432,8 @@ impl Memory {
 /// Keeps track of `Area`s, which are free-floating `Ui`s.
 /// These `Area`s can be in any `Order`.
 #[derive(Clone, Debug, Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct Areas {
     areas: HashMap<Id, area::State>,
     /// Back-to-front. Top is last.
diff --git a/egui/src/menu.rs b/egui/src/menu.rs
index 1d4e3c4d..8a96618a 100644
--- a/egui/src/menu.rs
+++ b/egui/src/menu.rs
@@ -20,8 +20,8 @@ use epaint::Stroke;
 
 /// What is saved between frames.
 #[derive(Clone, Copy, Debug, Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub(crate) struct BarState {
     open_menu: Option<Id>,
 }
diff --git a/egui/src/sense.rs b/egui/src/sense.rs
index 9a6b1aea..96f884e1 100644
--- a/egui/src/sense.rs
+++ b/egui/src/sense.rs
@@ -1,6 +1,6 @@
 /// What sort of interaction is a widget sensitive to?
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
-// #[cfg_attr(feature = "persistence", derive(serde::Serialize))]
+// #[cfg_attr(feature = "serde", derive(serde::Serialize))]
 pub struct Sense {
     /// buttons, sliders, windows ...
     pub click: bool,
diff --git a/egui/src/style.rs b/egui/src/style.rs
index bd4c3637..d09d5130 100644
--- a/egui/src/style.rs
+++ b/egui/src/style.rs
@@ -12,8 +12,8 @@ use epaint::{Shadow, Stroke, TextStyle};
 ///
 /// If you want to change fonts, use [`crate::Context::set_fonts`] instead.
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct Style {
     /// Default `TextStyle` for normal text (i.e. for `Label` and `TextEdit`).
     pub body_text_style: TextStyle,
@@ -81,8 +81,8 @@ impl Style {
 
 /// Controls the sizes and distances between widgets.
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct Spacing {
     /// Horizontal and vertical spacing between widgets.
     ///
@@ -151,8 +151,8 @@ impl Spacing {
 
 /// How and when interaction happens.
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct Interaction {
     /// Mouse must be the close to the side of a window to resize
     pub resize_grab_radius_side: f32,
@@ -171,8 +171,8 @@ pub struct Interaction {
 ///
 /// If you want to change fonts, use [`crate::Context::set_fonts`] instead.
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct Visuals {
     /// If true, the visuals are overall dark with light text.
     /// If false, the visuals are overall light with dark text.
@@ -270,8 +270,8 @@ impl Visuals {
 
 /// Selected text, selected elements etc
 #[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct Selection {
     pub bg_fill: Color32,
     pub stroke: Stroke,
@@ -279,8 +279,8 @@ pub struct Selection {
 
 /// The visuals of widgets for different states of interaction.
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct Widgets {
     /// The style of a widget that you cannot interact with.
     /// * `noninteractive.bg_stroke` is the outline of windows.
@@ -313,7 +313,7 @@ impl Widgets {
 
 /// bg = background, fg = foreground.
 #[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct WidgetVisuals {
     /// Background color of widget.
     pub bg_fill: Color32,
@@ -342,7 +342,7 @@ impl WidgetVisuals {
 
 /// Options for help debug egui by adding extra visualization
 #[derive(Clone, Copy, Debug, Default, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct DebugOptions {
     /// However over widgets to see their rectangles
     pub debug_on_hover: bool,
diff --git a/egui/src/util/undoer.rs b/egui/src/util/undoer.rs
index 66c4be99..ec57173c 100644
--- a/egui/src/util/undoer.rs
+++ b/egui/src/util/undoer.rs
@@ -1,7 +1,7 @@
 use std::collections::VecDeque;
 
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Settings {
     /// Maximum number of undos.
     /// If your state is resource intensive, you should keep this low.
@@ -48,7 +48,7 @@ impl Default for Settings {
 /// Rule 1) will make sure an undo point is not created until you _stop_ dragging that slider.
 /// Rule 2) will make sure that you will get some undo points even if you are constantly changing the state.
 #[derive(Clone, Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Undoer<State> {
     settings: Settings,
 
@@ -57,7 +57,7 @@ pub struct Undoer<State> {
     /// The latest undo point may (often) be the current state.
     undos: VecDeque<State>,
 
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     flux: Option<Flux<State>>,
 }
 
diff --git a/egui/src/widgets/plot/mod.rs b/egui/src/widgets/plot/mod.rs
index 60bc25d2..74b873e0 100644
--- a/egui/src/widgets/plot/mod.rs
+++ b/egui/src/widgets/plot/mod.rs
@@ -21,7 +21,7 @@ use color::Hsva;
 // ----------------------------------------------------------------------------
 
 /// Information about the plot that has to persist between frames.
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 #[derive(Clone)]
 struct PlotMemory {
     bounds: Bounds,
diff --git a/egui/src/widgets/plot/transform.rs b/egui/src/widgets/plot/transform.rs
index 138e75d0..9de9d32d 100644
--- a/egui/src/widgets/plot/transform.rs
+++ b/egui/src/widgets/plot/transform.rs
@@ -6,7 +6,7 @@ use crate::*;
 /// 2D bounding box of f64 precision.
 /// The range of data values we show.
 #[derive(Clone, Copy, PartialEq, Debug)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub(crate) struct Bounds {
     pub min: [f64; 2],
     pub max: [f64; 2],
diff --git a/egui/src/widgets/text_edit.rs b/egui/src/widgets/text_edit.rs
index 28d37194..8bd39994 100644
--- a/egui/src/widgets/text_edit.rs
+++ b/egui/src/widgets/text_edit.rs
@@ -4,25 +4,25 @@ use std::ops::Range;
 use std::sync::Arc;
 
 #[derive(Clone, Debug, Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub(crate) struct State {
     cursorp: Option<CursorPair>,
 
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     undoer: Undoer<(CCursorPair, String)>,
 
     // If IME candidate window is shown on this text edit.
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     has_ime: bool,
 
     // Visual offset when editing singleline text bigger than the width.
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     singleline_offset: f32,
 }
 
 #[derive(Clone, Copy, Debug, Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct CursorPair {
     /// When selecting with a mouse, this is where the mouse was released.
     /// When moving with e.g. shift+arrows, this is what moves.
@@ -86,7 +86,7 @@ impl CursorPair {
 }
 
 #[derive(Clone, Copy, Debug, Default, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 struct CCursorPair {
     /// When selecting with a mouse, this is where the mouse was released.
     /// When moving with e.g. shift+arrows, this is what moves.
diff --git a/egui_demo_lib/Cargo.toml b/egui_demo_lib/Cargo.toml
index 387539a3..236f16be 100644
--- a/egui_demo_lib/Cargo.toml
+++ b/egui_demo_lib/Cargo.toml
@@ -42,15 +42,17 @@ criterion = { version = "0.3", default-features = false }
 
 [features]
 default = []
-http = ["ehttp", "image"]
-persistence = ["egui/persistence", "epi/persistence", "serde"]
-syntax_highlighting = ["syntect"]
 
 # Enable additional checks if debug assertions are enabled (debug builds).
 extra_debug_asserts = ["egui/extra_debug_asserts"]
 # Always enable additional checks.
 extra_asserts = ["egui/extra_asserts"]
 
+http = ["ehttp", "image"]
+persistence = ["egui/persistence", "epi/persistence", "serde"]
+serialize = ["egui/serialize",  "serde"]
+syntax_highlighting = ["syntect"]
+
 [[bench]]
 name = "benchmark"
 harness = false
diff --git a/egui_demo_lib/src/apps/color_test.rs b/egui_demo_lib/src/apps/color_test.rs
index c3ed9e9a..2303e2d2 100644
--- a/egui_demo_lib/src/apps/color_test.rs
+++ b/egui_demo_lib/src/apps/color_test.rs
@@ -9,9 +9,9 @@ const RED: Color32 = Color32::RED;
 const TRANSPARENT: Color32 = Color32::TRANSPARENT;
 const WHITE: Color32 = Color32::WHITE;
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct ColorTest {
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     tex_mngr: TextureManager,
     vertex_gradients: bool,
     texture_gradients: bool,
diff --git a/egui_demo_lib/src/apps/demo/app.rs b/egui_demo_lib/src/apps/demo/app.rs
index 51d4f30e..75d777e2 100644
--- a/egui_demo_lib/src/apps/demo/app.rs
+++ b/egui_demo_lib/src/apps/demo/app.rs
@@ -3,8 +3,8 @@
 /// Implements `epi::App` so it can be used with
 /// [`egui_glium`](https://crates.io/crates/egui_glium) and [`egui_web`](https://crates.io/crates/egui_web).
 #[derive(Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct DemoApp {
     demo_windows: super::DemoWindows,
 }
@@ -14,14 +14,14 @@ impl epi::App for DemoApp {
         "✨ Demos"
     }
 
-    #[cfg(feature = "persistence")]
     fn setup(
         &mut self,
         _ctx: &egui::CtxRef,
         _frame: &mut epi::Frame<'_>,
-        storage: Option<&dyn epi::Storage>,
+        _storage: Option<&dyn epi::Storage>,
     ) {
-        if let Some(storage) = storage {
+        #[cfg(feature = "persistence")]
+        if let Some(storage) = _storage {
             *self = epi::get_value(storage, epi::APP_KEY).unwrap_or_default()
         }
     }
diff --git a/egui_demo_lib/src/apps/demo/code_editor.rs b/egui_demo_lib/src/apps/demo/code_editor.rs
index 56b7f421..7dc825b3 100644
--- a/egui_demo_lib/src/apps/demo/code_editor.rs
+++ b/egui_demo_lib/src/apps/demo/code_editor.rs
@@ -1,11 +1,11 @@
 use egui::text::LayoutJob;
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct CodeEditor {
     code: String,
     language: String,
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     highlighter: MemoizedSyntaxHighlighter,
 }
 
diff --git a/egui_demo_lib/src/apps/demo/dancing_strings.rs b/egui_demo_lib/src/apps/demo/dancing_strings.rs
index 94beb42d..22ae4f3c 100644
--- a/egui_demo_lib/src/apps/demo/dancing_strings.rs
+++ b/egui_demo_lib/src/apps/demo/dancing_strings.rs
@@ -1,8 +1,8 @@
 use egui::{containers::*, *};
 
 #[derive(Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct DancingStrings {}
 
 impl super::Demo for DancingStrings {
diff --git a/egui_demo_lib/src/apps/demo/demo_app_windows.rs b/egui_demo_lib/src/apps/demo/demo_app_windows.rs
index b5403d13..3fefb810 100644
--- a/egui_demo_lib/src/apps/demo/demo_app_windows.rs
+++ b/egui_demo_lib/src/apps/demo/demo_app_windows.rs
@@ -4,10 +4,10 @@ use std::collections::BTreeSet;
 
 // ----------------------------------------------------------------------------
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 struct Demos {
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     demos: Vec<Box<dyn Demo>>,
 
     open: BTreeSet<String>,
@@ -67,10 +67,10 @@ impl Demos {
 
 // ----------------------------------------------------------------------------
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 struct Tests {
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     demos: Vec<Box<dyn Demo>>,
 
     open: BTreeSet<String>,
@@ -136,8 +136,8 @@ fn set_open(open: &mut BTreeSet<String>, key: &'static str, is_open: bool) {
 
 /// A menu bar in which you can select different demo windows to show.
 #[derive(Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct DemoWindows {
     demos: Demos,
     tests: Tests,
diff --git a/egui_demo_lib/src/apps/demo/layout_test.rs b/egui_demo_lib/src/apps/demo/layout_test.rs
index e73044d5..be7fc5c8 100644
--- a/egui_demo_lib/src/apps/demo/layout_test.rs
+++ b/egui_demo_lib/src/apps/demo/layout_test.rs
@@ -1,7 +1,7 @@
 use egui::*;
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct LayoutTest {
     // Identical to contents of `egui::Layout`
     layout: LayoutSettings,
@@ -22,8 +22,8 @@ impl Default for LayoutTest {
 }
 
 #[derive(Clone, Copy, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct LayoutSettings {
     // Similar to the contents of `egui::Layout`
     main_dir: Direction,
diff --git a/egui_demo_lib/src/apps/demo/misc_demo_window.rs b/egui_demo_lib/src/apps/demo/misc_demo_window.rs
index eaac01e2..31b03d0e 100644
--- a/egui_demo_lib/src/apps/demo/misc_demo_window.rs
+++ b/egui_demo_lib/src/apps/demo/misc_demo_window.rs
@@ -2,8 +2,8 @@ use super::*;
 use egui::{color::*, *};
 
 /// Showcase some ui code
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct MiscDemoWindow {
     num_columns: usize,
 
@@ -115,8 +115,8 @@ impl View for MiscDemoWindow {
 
 // ----------------------------------------------------------------------------
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct Widgets {
     angle: f32,
     password: String,
@@ -194,8 +194,8 @@ impl Widgets {
 // ----------------------------------------------------------------------------
 
 #[derive(PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 struct ColorWidgets {
     srgba_unmul: [u8; 4],
     srgba_premul: [u8; 4],
@@ -264,8 +264,8 @@ impl ColorWidgets {
 
 // ----------------------------------------------------------------------------
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 struct BoxPainting {
     size: Vec2,
     corner_radius: f32,
@@ -315,7 +315,7 @@ enum Action {
 }
 
 #[derive(Clone, Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 struct Tree(String, SubTree);
 
 impl Tree {
@@ -334,7 +334,7 @@ impl Tree {
 }
 
 #[derive(Clone, Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 struct SubTree(Vec<SubTree>);
 
 impl SubTree {
diff --git a/egui_demo_lib/src/apps/demo/painting.rs b/egui_demo_lib/src/apps/demo/painting.rs
index ed4f4932..1c2c2e95 100644
--- a/egui_demo_lib/src/apps/demo/painting.rs
+++ b/egui_demo_lib/src/apps/demo/painting.rs
@@ -1,7 +1,7 @@
 use egui::*;
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct Painting {
     /// in 0-1 normalized coordinates
     lines: Vec<Vec<Pos2>>,
diff --git a/egui_demo_lib/src/apps/demo/scrolling.rs b/egui_demo_lib/src/apps/demo/scrolling.rs
index 2b388085..fdbd2ff5 100644
--- a/egui_demo_lib/src/apps/demo/scrolling.rs
+++ b/egui_demo_lib/src/apps/demo/scrolling.rs
@@ -1,6 +1,6 @@
 use egui::{color::*, *};
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 #[derive(Clone, Copy, Debug, PartialEq)]
 enum ScrollDemo {
     ScrollTo,
@@ -14,8 +14,8 @@ impl Default for ScrollDemo {
     }
 }
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 #[derive(Default, PartialEq)]
 pub struct Scrolling {
     demo: ScrollDemo,
@@ -124,8 +124,8 @@ fn huge_content_painter(ui: &mut egui::Ui) {
 
 // ----------------------------------------------------------------------------
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 #[derive(PartialEq)]
 struct ScrollTo {
     track_item: usize,
diff --git a/egui_demo_lib/src/apps/demo/sliders.rs b/egui_demo_lib/src/apps/demo/sliders.rs
index 195a45ea..c1c7947e 100644
--- a/egui_demo_lib/src/apps/demo/sliders.rs
+++ b/egui_demo_lib/src/apps/demo/sliders.rs
@@ -3,8 +3,8 @@ use std::f64::INFINITY;
 
 /// Showcase sliders
 #[derive(PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct Sliders {
     pub min: f64,
     pub max: f64,
diff --git a/egui_demo_lib/src/apps/demo/tests.rs b/egui_demo_lib/src/apps/demo/tests.rs
index cacba26a..25178313 100644
--- a/egui_demo_lib/src/apps/demo/tests.rs
+++ b/egui_demo_lib/src/apps/demo/tests.rs
@@ -303,7 +303,7 @@ impl super::View for TableTest {
 
 // ----------------------------------------------------------------------------
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 #[derive(Default)]
 pub struct InputTest {
     info: String,
diff --git a/egui_demo_lib/src/apps/demo/widget_gallery.rs b/egui_demo_lib/src/apps/demo/widget_gallery.rs
index 6e485691..9519ac2e 100644
--- a/egui_demo_lib/src/apps/demo/widget_gallery.rs
+++ b/egui_demo_lib/src/apps/demo/widget_gallery.rs
@@ -1,5 +1,5 @@
 #[derive(Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 enum Enum {
     First,
     Second,
@@ -7,7 +7,7 @@ enum Enum {
 }
 
 /// Shows off one example of each major type of widget.
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct WidgetGallery {
     enabled: bool,
     visible: bool,
diff --git a/egui_demo_lib/src/apps/demo/window_options.rs b/egui_demo_lib/src/apps/demo/window_options.rs
index b0b3b60c..db31da48 100644
--- a/egui_demo_lib/src/apps/demo/window_options.rs
+++ b/egui_demo_lib/src/apps/demo/window_options.rs
@@ -1,5 +1,5 @@
 #[derive(Clone, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct WindowOptions {
     title: String,
     title_bar: bool,
diff --git a/egui_demo_lib/src/apps/demo/window_with_panels.rs b/egui_demo_lib/src/apps/demo/window_with_panels.rs
index 1653d32f..c9e1dfec 100644
--- a/egui_demo_lib/src/apps/demo/window_with_panels.rs
+++ b/egui_demo_lib/src/apps/demo/window_with_panels.rs
@@ -1,5 +1,5 @@
 #[derive(Clone, PartialEq, Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct WindowWithPanels {}
 
 impl super::Demo for WindowWithPanels {
diff --git a/egui_demo_lib/src/apps/fractal_clock.rs b/egui_demo_lib/src/apps/fractal_clock.rs
index d7b94e53..5a23f5fb 100644
--- a/egui_demo_lib/src/apps/fractal_clock.rs
+++ b/egui_demo_lib/src/apps/fractal_clock.rs
@@ -2,8 +2,8 @@ use egui::{containers::*, widgets::*, *};
 use std::f32::consts::TAU;
 
 #[derive(PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct FractalClock {
     paused: bool,
     time: f64,
diff --git a/egui_demo_lib/src/apps/http_app.rs b/egui_demo_lib/src/apps/http_app.rs
index 79701233..9946066e 100644
--- a/egui_demo_lib/src/apps/http_app.rs
+++ b/egui_demo_lib/src/apps/http_app.rs
@@ -38,13 +38,13 @@ impl Resource {
 }
 
 #[derive(Debug, PartialEq, Copy, Clone)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 enum Method {
     Get,
     Post,
 }
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct HttpApp {
     url: String,
 
@@ -52,13 +52,13 @@ pub struct HttpApp {
 
     request_body: String,
 
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     in_progress: Option<Receiver<Result<ehttp::Response, String>>>,
 
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     result: Option<Result<Resource, String>>,
 
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     tex_mngr: TexMngr,
 }
 
diff --git a/egui_demo_lib/src/backend_panel.rs b/egui_demo_lib/src/backend_panel.rs
index a24ce8e4..16666384 100644
--- a/egui_demo_lib/src/backend_panel.rs
+++ b/egui_demo_lib/src/backend_panel.rs
@@ -41,12 +41,12 @@ impl Default for RunMode {
 
 // ----------------------------------------------------------------------------
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct BackendPanel {
     pub open: bool,
 
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     // go back to `Reactive` mode each time we start
     run_mode: RunMode,
 
@@ -57,10 +57,10 @@ pub struct BackendPanel {
     max_size_points_ui: egui::Vec2,
     pub max_size_points_active: egui::Vec2,
 
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     frame_history: crate::frame_history::FrameHistory,
 
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     output_event_history: std::collections::VecDeque<egui::output::OutputEvent>,
 
     egui_windows: EguiWindows,
@@ -286,7 +286,7 @@ impl BackendPanel {
 
 // ----------------------------------------------------------------------------
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 struct EguiWindows {
     // egui stuff:
     settings: bool,
diff --git a/egui_demo_lib/src/easy_mark/easy_mark_editor.rs b/egui_demo_lib/src/easy_mark/easy_mark_editor.rs
index 746eeece..f0c85ecb 100644
--- a/egui_demo_lib/src/easy_mark/easy_mark_editor.rs
+++ b/egui_demo_lib/src/easy_mark/easy_mark_editor.rs
@@ -1,13 +1,13 @@
 use egui::*;
 
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct EasyMarkEditor {
     code: String,
     highlight_editor: bool,
     show_rendered: bool,
 
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     highlighter: crate::easy_mark::MemoizedEasymarkHighlighter,
 }
 
diff --git a/egui_demo_lib/src/wrap_app.rs b/egui_demo_lib/src/wrap_app.rs
index e93b1c10..5559fd84 100644
--- a/egui_demo_lib/src/wrap_app.rs
+++ b/egui_demo_lib/src/wrap_app.rs
@@ -1,7 +1,7 @@
 /// All the different demo apps.
 #[derive(Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct Apps {
     demo: crate::apps::DemoApp,
     easy_mark_editor: crate::easy_mark::EasyMarkEditor,
@@ -27,13 +27,13 @@ impl Apps {
 
 /// Wraps many demo/test apps into one.
 #[derive(Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct WrapApp {
     selected_anchor: String,
     apps: Apps,
     backend_panel: super::backend_panel::BackendPanel,
-    #[cfg_attr(feature = "persistence", serde(skip))]
+    #[cfg_attr(feature = "serde", serde(skip))]
     dropped_files: Vec<egui::DroppedFile>,
 }
 
@@ -42,15 +42,14 @@ impl epi::App for WrapApp {
         "egui demo apps"
     }
 
-    #[allow(unused_variables)]
     fn setup(
         &mut self,
         _ctx: &egui::CtxRef,
         _frame: &mut epi::Frame<'_>,
-        storage: Option<&dyn epi::Storage>,
+        _storage: Option<&dyn epi::Storage>,
     ) {
         #[cfg(feature = "persistence")]
-        if let Some(storage) = storage {
+        if let Some(storage) = _storage {
             *self = epi::get_value(storage, epi::APP_KEY).unwrap_or_default()
         }
     }
diff --git a/egui_glium/src/backend.rs b/egui_glium/src/backend.rs
index 61673e6b..8befea20 100644
--- a/egui_glium/src/backend.rs
+++ b/egui_glium/src/backend.rs
@@ -361,12 +361,16 @@ pub fn run(mut app: Box<dyn epi::App>, native_options: &epi::NativeOptions) {
             if let Some(storage) = &mut storage {
                 let now = Instant::now();
                 if now - last_auto_save > app.auto_save_interval() {
-                    epi::set_value(
-                        storage.as_mut(),
-                        WINDOW_KEY,
-                        &WindowSettings::from_display(&display),
-                    );
-                    epi::set_value(storage.as_mut(), EGUI_MEMORY_KEY, &*egui.ctx().memory());
+                    if app.persist_native_window() {
+                        epi::set_value(
+                            storage.as_mut(),
+                            WINDOW_KEY,
+                            &WindowSettings::from_display(&display),
+                        );
+                    }
+                    if app.persist_egui_memory() {
+                        epi::set_value(storage.as_mut(), EGUI_MEMORY_KEY, &*egui.ctx().memory());
+                    }
                     app.save(storage.as_mut());
                     storage.flush();
                     last_auto_save = now;
@@ -379,12 +383,16 @@ pub fn run(mut app: Box<dyn epi::App>, native_options: &epi::NativeOptions) {
 
     #[cfg(feature = "persistence")]
     if let Some(storage) = &mut storage {
-        epi::set_value(
-            storage.as_mut(),
-            WINDOW_KEY,
-            &WindowSettings::from_display(&display),
-        );
-        epi::set_value(storage.as_mut(), EGUI_MEMORY_KEY, &*egui.ctx().memory());
+        if app.persist_native_window() {
+            epi::set_value(
+                storage.as_mut(),
+                WINDOW_KEY,
+                &WindowSettings::from_display(&display),
+            );
+        }
+        if app.persist_egui_memory() {
+            epi::set_value(storage.as_mut(), EGUI_MEMORY_KEY, &*egui.ctx().memory());
+        }
         app.save(storage.as_mut());
         storage.flush();
     }
diff --git a/egui_web/src/backend.rs b/egui_web/src/backend.rs
index ffa1be43..583e06ab 100644
--- a/egui_web/src/backend.rs
+++ b/egui_web/src/backend.rs
@@ -194,7 +194,9 @@ impl AppRunner {
         let time_since_last_save = now - self.last_save_time;
 
         if time_since_last_save > self.app.auto_save_interval().as_secs_f64() {
-            save_memory(&self.web_backend.egui_ctx);
+            if self.app.persist_egui_memory() {
+                save_memory(&self.web_backend.egui_ctx);
+            }
             self.app.save(&mut self.storage);
             self.last_save_time = now;
         }
diff --git a/epaint/Cargo.toml b/epaint/Cargo.toml
index 2c8aeae4..bf026854 100644
--- a/epaint/Cargo.toml
+++ b/epaint/Cargo.toml
@@ -50,7 +50,8 @@ extra_asserts = ["emath/extra_asserts"]
 # Add compatability with https://github.com/kvark/mint
 mint = ["emath/mint"]
 
-persistence = ["serde", "emath/serde"]
+# implement serde on most types.
+serialize = ["serde", "emath/serde"]
 
 single_threaded = ["atomic_refcell"]
 
diff --git a/epaint/src/color.rs b/epaint/src/color.rs
index 5d390fc4..df840eea 100644
--- a/epaint/src/color.rs
+++ b/epaint/src/color.rs
@@ -14,7 +14,7 @@
 /// Internally this uses 0-255 gamma space `sRGBA` color with premultiplied alpha.
 /// Alpha channel is in linear space.
 #[derive(Clone, Copy, Debug, Default, Eq, Hash, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Color32(pub(crate) [u8; 4]);
 
 impl std::ops::Index<usize> for Color32 {
@@ -184,7 +184,7 @@ impl Color32 {
 
 /// 0-1 linear space `RGBA` color with premultiplied alpha.
 #[derive(Clone, Copy, Debug, Default, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Rgba(pub(crate) [f32; 4]);
 
 impl std::ops::Index<usize> for Rgba {
diff --git a/epaint/src/lib.rs b/epaint/src/lib.rs
index e63de097..9918d82a 100644
--- a/epaint/src/lib.rs
+++ b/epaint/src/lib.rs
@@ -109,7 +109,7 @@ pub const WHITE_UV: emath::Pos2 = emath::pos2(0.0, 0.0);
 
 /// What texture to use in a [`Mesh`] mesh.
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub enum TextureId {
     /// The egui font texture.
     /// If you don't want to use a texture, pick this and the [`WHITE_UV`] for uv-coord.
@@ -142,7 +142,7 @@ pub struct ClippedShape(
 ///
 /// Everything is using logical points.
 #[derive(Clone, Debug)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct ClippedMesh(
     /// Clip / scissor rectangle.
     /// Only show the part of the [`Mesh`] that falls within this.
diff --git a/epaint/src/mesh.rs b/epaint/src/mesh.rs
index 1deff677..bb947e8c 100644
--- a/epaint/src/mesh.rs
+++ b/epaint/src/mesh.rs
@@ -6,7 +6,7 @@ use emath::*;
 /// Should be friendly to send to GPU as is.
 #[repr(C)]
 #[derive(Clone, Copy, Debug, Default, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Vertex {
     /// Logical pixel coordinates (points).
     /// (0,0) is the top left corner of the screen.
@@ -23,7 +23,7 @@ pub struct Vertex {
 
 /// Textured triangles in two dimensions.
 #[derive(Clone, Debug, Default, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Mesh {
     /// Draw as triangles (i.e. the length is always multiple of three).
     ///
diff --git a/epaint/src/shadow.rs b/epaint/src/shadow.rs
index a9e8ab8e..89a132fa 100644
--- a/epaint/src/shadow.rs
+++ b/epaint/src/shadow.rs
@@ -3,7 +3,7 @@ use super::*;
 /// The color and fuzziness of a fuzzy shape.
 /// Can be used for a rectangular shadow with a soft penumbra.
 #[derive(Clone, Copy, Debug, Default, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Shadow {
     /// The shadow extends this much outside the rect.
     /// The size of the fuzzy penumbra.
diff --git a/epaint/src/shape.rs b/epaint/src/shape.rs
index f6161aaf..cde0c1a9 100644
--- a/epaint/src/shape.rs
+++ b/epaint/src/shape.rs
@@ -129,7 +129,7 @@ impl Shape {
 
 /// How to paint a circle.
 #[derive(Copy, Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct CircleShape {
     pub center: Pos2,
     pub radius: f32,
@@ -170,7 +170,7 @@ impl From<CircleShape> for Shape {
 
 /// A path which can be stroked and/or filled (if closed).
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct PathShape {
     pub points: Vec<Pos2>,
     /// If true, connect the first and last of the points together.
@@ -239,7 +239,7 @@ impl From<PathShape> for Shape {
 
 /// How to paint a rectangle.
 #[derive(Copy, Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct RectShape {
     pub rect: Rect,
     /// How rounded the corners are. Use `0.0` for no rounding.
diff --git a/epaint/src/stroke.rs b/epaint/src/stroke.rs
index ffe34f46..04a1efb9 100644
--- a/epaint/src/stroke.rs
+++ b/epaint/src/stroke.rs
@@ -6,7 +6,7 @@ use super::*;
 ///
 /// The default stroke is the same as [`Stroke::none`].
 #[derive(Clone, Copy, Debug, Default, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Stroke {
     pub width: f32,
     pub color: Color32,
diff --git a/epaint/src/tessellator.rs b/epaint/src/tessellator.rs
index d25a6646..78b22993 100644
--- a/epaint/src/tessellator.rs
+++ b/epaint/src/tessellator.rs
@@ -254,8 +254,8 @@ pub enum PathType {
 
 /// Tessellation quality options
 #[derive(Clone, Copy, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct TessellationOptions {
     /// Size of a point in pixels, e.g. 2.0. Used to snap text to pixel boundaries.
     pub pixels_per_point: f32,
diff --git a/epaint/src/text/cursor.rs b/epaint/src/text/cursor.rs
index 5403fd2a..9967853c 100644
--- a/epaint/src/text/cursor.rs
+++ b/epaint/src/text/cursor.rs
@@ -2,7 +2,7 @@
 
 /// Character cursor
 #[derive(Clone, Copy, Debug, Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct CCursor {
     /// Character offset (NOT byte offset!).
     pub index: usize,
@@ -65,7 +65,7 @@ impl std::ops::SubAssign<usize> for CCursor {
 
 /// Row Cursor
 #[derive(Clone, Copy, Debug, Default, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct RCursor {
     /// 0 is first row, and so on.
     /// Note that a single paragraph can span multiple rows.
@@ -80,7 +80,7 @@ pub struct RCursor {
 
 /// Paragraph Cursor
 #[derive(Clone, Copy, Debug, Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct PCursor {
     /// 0 is first paragraph, and so on.
     /// Note that a single paragraph can span multiple rows.
@@ -112,7 +112,7 @@ impl PartialEq for PCursor {
 /// pcursor/rcursor can also point to after the end of the paragraph/row.
 /// Does not implement `PartialEq` because you must think which cursor should be equivalent.
 #[derive(Clone, Copy, Debug, Default)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Cursor {
     pub ccursor: CCursor,
     pub rcursor: RCursor,
diff --git a/epaint/src/text/fonts.rs b/epaint/src/text/fonts.rs
index f90a46f3..73d95f9f 100644
--- a/epaint/src/text/fonts.rs
+++ b/epaint/src/text/fonts.rs
@@ -12,8 +12,8 @@ use crate::{
 // TODO: rename
 /// One of a few categories of styles of text, e.g. body, button or heading.
 #[derive(Copy, Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(rename_all = "snake_case"))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(rename_all = "snake_case"))]
 pub enum TextStyle {
     /// Used when small text is needed.
     Small,
@@ -43,8 +43,8 @@ impl TextStyle {
 
 /// Which style of font: [`Monospace`][`FontFamily::Monospace`] or [`Proportional`][`FontFamily::Proportional`].
 #[derive(Copy, Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(rename_all = "snake_case"))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(rename_all = "snake_case"))]
 pub enum FontFamily {
     /// A font where each character is the same width (`w` is the same width as `i`).
     Monospace,
@@ -106,8 +106,8 @@ fn ab_glyph_font_from_font_data(name: &str, data: &FontData) -> ab_glyph::FontAr
 /// ctx.set_fonts(fonts);
 /// ```
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
-#[cfg_attr(feature = "persistence", serde(default))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
 pub struct FontDefinitions {
     /// List of font names and their definitions.
     /// The definition must be the contents of either a `.ttf` or `.otf` font file.
diff --git a/epaint/src/text/text_layout_types.rs b/epaint/src/text/text_layout_types.rs
index f5bf2343..c9a49dec 100644
--- a/epaint/src/text/text_layout_types.rs
+++ b/epaint/src/text/text_layout_types.rs
@@ -13,7 +13,7 @@ use emath::*;
 ///
 /// Pass this to [`Fonts::layout_job]` or [`crate::text::layout`].
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct LayoutJob {
     /// The complete text of this job, referenced by `LayoutSection`.
     pub text: String, // TODO: Cow<'static, str>
@@ -137,7 +137,7 @@ impl std::hash::Hash for LayoutJob {
 // ----------------------------------------------------------------------------
 
 #[derive(Clone, Debug, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct LayoutSection {
     /// Can be used for first row indentation.
     pub leading_space: f32,
@@ -163,7 +163,7 @@ impl std::hash::Hash for LayoutSection {
 // ----------------------------------------------------------------------------
 
 #[derive(Copy, Clone, Debug, Hash, PartialEq)]
-#[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct TextFormat {
     pub style: TextStyle,
     /// Text color
diff --git a/epi/src/lib.rs b/epi/src/lib.rs
index 0bb2b43a..1a7d548a 100644
--- a/epi/src/lib.rs
+++ b/epi/src/lib.rs
@@ -94,7 +94,7 @@ pub trait App {
     /// Allows you to do setup code, e.g to call `[egui::Context::set_fonts]`,
     /// `[egui::Context::set_visuals]` etc.
     ///
-    /// Also allows you to restore state, if there is a storage.
+    /// Also allows you to restore state, if there is a storage (required the "persistence" feature).
     fn setup(
         &mut self,
         _ctx: &egui::CtxRef,
@@ -113,6 +113,8 @@ pub trait App {
 
     /// Called on shutdown, and perhaps at regular intervals. Allows you to save state.
     ///
+    /// Only called when the "persistence" feature is enabled.
+    ///
     /// On web the states is stored to "Local Storage".
     /// On native the path is picked using [`directories_next::ProjectDirs::data_dir`](https://docs.rs/directories-next/2.0.0/directories_next/struct.ProjectDirs.html#method.data_dir) which is:
     /// * Linux:   `/home/UserName/.local/share/APPNAME`
@@ -150,6 +152,18 @@ pub trait App {
         // `transparent()` option they get immediate results.
         egui::Color32::from_rgba_unmultiplied(12, 12, 12, 180).into()
     }
+
+    /// Controls wether or not the native window position and size will be
+    /// persisted (only if the "persistence" feature is enabled).
+    fn persist_native_window(&self) -> bool {
+        true
+    }
+
+    /// Controls wether or not the egui memory (window positions etc) will be
+    /// persisted (only if the "persistence" feature is enabled).
+    fn persist_egui_memory(&self) -> bool {
+        true
+    }
 }
 
 /// Options controlling the behavior of a native window