Fix focus tracking

Author: emilk

crates/eframe/src/web/app_runner.rs

@@ -187,6 +187,10 @@ impl AppRunner {
     ///
     /// The result can be painted later with a call to [`Self::run_and_paint`] or [`Self::paint`].
     pub fn logic(&mut self) {
+        // We sometimes miss blur/focus events due to the text agent, so let's just poll each frame:
+        self.input
+            .set_focus(super::has_focus(self.canvas()) || self.text_agent.has_focus());
+
         let canvas_size = super::canvas_size_in_points(self.canvas(), self.egui_ctx());
         let mut raw_input = self.input.new_frame(canvas_size);
 

crates/eframe/src/web/backend.rs

@@ -36,8 +36,12 @@ impl WebInput {
         raw_input
     }
 
-    /// On alt-tab and similar.
-    pub fn on_web_page_focus_change(&mut self, focused: bool) {
+    /// On alt-tab, or user clicking another HTML element.
+    pub fn set_focus(&mut self, focused: bool) {
+        if self.raw.focused == focused {
+            return;
+        }
+
         // log::debug!("on_web_page_focus_change: {focused}");
         self.raw.modifiers = egui::Modifiers::default(); // Avoid sticky modifier keys on alt-tab:
         self.raw.focused = focused;

crates/eframe/src/web/events.rs

@@ -105,7 +105,7 @@ fn install_blur_focus(runner_ref: &WebRunner, target: &EventTarget) -> Result<()
                 runner.save();
             }
 
-            runner.input.on_web_page_focus_change(has_focus);
+            runner.input.set_focus(has_focus);
             runner.egui_ctx().request_repaint();
         };