From 04c3efd01aee4edc2e36a0bdb0d0ad123e2096e4 Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
Date: Wed, 26 Jan 2022 14:44:10 +0100
Subject: [PATCH] Minor optimization: avoid reallocating set of visible ID:s

---
 egui/src/memory.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/egui/src/memory.rs b/egui/src/memory.rs
index 4afdfeb8..c367d205 100644
--- a/egui/src/memory.rs
+++ b/egui/src/memory.rs
@@ -568,7 +568,8 @@ impl Areas {
             ..
         } = self;
 
-        *visible_last_frame = std::mem::take(visible_current_frame);
+        std::mem::swap(visible_last_frame, visible_current_frame);
+        visible_current_frame.clear();
         order.sort_by_key(|layer| (layer.order, wants_to_be_on_top.contains(layer)));
         wants_to_be_on_top.clear();
     }