x11: allow configuration of repaint delay

Adds a configuration option, `focus_change_repaint_delay` to allow customisation of the delay added in 9b6329b.

The default delay remains 100ms, and can be disabled by setting it to `0`, if the workaround is not required on the user's system.

refs: wez#2063
refs: wez#1992

config/src/config.rs

@@ -648,6 +648,9 @@ pub struct Config {
 
     #[dynamic(default)]
     pub quote_dropped_files: DroppedFileQuoting,
+
+    #[dynamic(default = "default_focus_change_repaint_delay")]
+    pub focus_change_repaint_delay: u64,
 }
 impl_lua_conversion_dynamic!(Config);
 
@@ -1346,6 +1349,10 @@ fn default_inactive_pane_hsb() -> HsbTransform {
     }
 }
 
+fn default_focus_change_repaint_delay() -> u64 {
+    100
+}
+
 #[derive(FromDynamic, ToDynamic, Clone, Copy, Debug)]
 pub enum DefaultCursorStyle {
     BlinkingBlock,

docs/config/lua/config/focus_change_repaint_delay.md

@@ -0,0 +1,8 @@
+## `focus_change_repaint_delay = 100`
+
+*Since: nightly builds only*
+
+When not set to `0`, WezTerm will wait the specified delay (in milliseconds) before invalidating the geometry and repainting the window after losing or gaining focus.
+
+Using the proprietry NVIDIA drivers and EGL rendering on X11, the `CONFIGURE_NOTIFY` event is sometimes missed. This workaround ensures that the window correctly resizes in these cases.
+

window/src/os/x11/window.rs

@@ -557,16 +557,19 @@ impl XWindowInner {
         // the window a short time after the focus event is processed in the
         // hope that it can observe the changed window properties and update
         // without the human needing to interact with the window.
-        let window_id = self.window_id;
-        promise::spawn::spawn(async move {
-            async_io::Timer::after(std::time::Duration::from_millis(100)).await;
-            XConnection::with_window_inner(window_id, |inner| {
-                inner.sure_about_geometry = false;
-                inner.invalidate();
-                Ok(())
-            });
-        })
-        .detach();
+        let delay = self.config.focus_change_repaint_delay;
+        if delay != 0 {
+            let window_id = self.window_id;
+            promise::spawn::spawn(async move {
+                async_io::Timer::after(std::time::Duration::from_millis(delay)).await;
+                XConnection::with_window_inner(window_id, |inner| {
+                    inner.sure_about_geometry = false;
+                    inner.invalidate();
+                    Ok(())
+                });
+            })
+            .detach();
+        }
     }
 
     pub fn dispatch_ime_compose_status(&mut self, status: DeadKeyStatus) {