From 02389a257897dd18998cb17065f41b26391df398 Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
Date: Tue, 4 Aug 2026 14:11:56 +0200
Subject: [PATCH] Remove ThemeCache, since it is buggy

---
 crates/egui/src/theme/mod.rs         |  3 +-
 crates/egui/src/theme/theme_cache.rs | 41 ----------------------------
 examples/styling_engine/src/main.rs  |  1 -
 3 files changed, 1 insertion(+), 44 deletions(-)
 delete mode 100644 crates/egui/src/theme/theme_cache.rs

diff --git a/crates/egui/src/theme/mod.rs b/crates/egui/src/theme/mod.rs
index 9aa880831..bd7bc484d 100644
--- a/crates/egui/src/theme/mod.rs
+++ b/crates/egui/src/theme/mod.rs
@@ -2,10 +2,9 @@
 
 mod default_style;
 mod style_provider;
-mod theme_cache;
 mod themes;
 
-pub use self::{style_provider::StyleProvider, theme_cache::ThemeCache, themes::Themes};
+pub use self::{style_provider::StyleProvider, themes::Themes};
 
 use crate::{
     Ui,
diff --git a/crates/egui/src/theme/theme_cache.rs b/crates/egui/src/theme/theme_cache.rs
deleted file mode 100644
index f9b2cdcaa..000000000
--- a/crates/egui/src/theme/theme_cache.rs
+++ /dev/null
@@ -1,41 +0,0 @@
-use crate::{
-    Id,
-    theme::StyleProvider,
-    util::IdTypeMap,
-    widget_style::{StyleArgs, WidgetStyle},
-};
-
-/// A cache that can be implemented to reduce computation time of a `StyleProvider`
-#[derive(Debug, Default, Clone)]
-pub struct ThemeCache<Theme> {
-    cache: IdTypeMap,
-    inner: Theme,
-}
-
-impl<Theme> ThemeCache<Theme> {
-    pub fn new(theme: Theme) -> Self {
-        Self {
-            cache: IdTypeMap::default(),
-            inner: theme,
-        }
-    }
-}
-
-impl<Theme: StyleProvider<S>, S: WidgetStyle> StyleProvider<S> for ThemeCache<Theme> {
-    /// Access the cache for the requested [`WidgetStyle`] based on the [`Classes`](crate::widget_style::Classes) and
-    /// the [`WidgetState`](crate::widget_style::WidgetState)
-    ///
-    /// If no entry match the parameter then compute the fallback style and
-    /// save the output for later.
-    fn style(&mut self, modifiers: &StyleArgs<'_>) -> S {
-        let StyleArgs { classes, state, .. } = modifiers;
-        let style_id = Id::new((classes, state));
-        if let Some(style) = self.cache.get_temp::<S>(style_id) {
-            style
-        } else {
-            let style = self.inner.style(modifiers);
-            self.cache.insert_temp(style_id, style.clone());
-            style
-        }
-    }
-}
diff --git a/examples/styling_engine/src/main.rs b/examples/styling_engine/src/main.rs
index d9503a3e6..80b27795d 100644
--- a/examples/styling_engine/src/main.rs
+++ b/examples/styling_engine/src/main.rs
@@ -93,7 +93,6 @@ fn main() -> eframe::Result {
 
     eframe::run_ui_native("Styling engine", options, move |ui, _frame| {
         // Register our theme for all buttons. This is a no-op after the first frame.
-        // Wrap it in a `ThemeCache` if computing the style is expensive.
         ui.add_widget_theme::<ButtonStyle>(theme);
 
         Panel::left("controls").default_size(260.0).show(ui, |ui| {