diff -up firefox-100.0/widget/gtk/nsWindow.cpp.1196777 firefox-100.0/widget/gtk/nsWindow.cpp
--- firefox-100.0/widget/gtk/nsWindow.cpp.1196777	2022-05-02 11:29:06.763325015 +0200
+++ firefox-100.0/widget/gtk/nsWindow.cpp	2022-05-02 11:30:49.100717334 +0200
@@ -163,7 +163,8 @@ const gint kEvents = GDK_TOUCHPAD_GESTUR
                      GDK_ENTER_NOTIFY_MASK | GDK_LEAVE_NOTIFY_MASK |
                      GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK |
                      GDK_SMOOTH_SCROLL_MASK | GDK_TOUCH_MASK | GDK_SCROLL_MASK |
-                     GDK_POINTER_MOTION_MASK | GDK_PROPERTY_CHANGE_MASK;
+                     GDK_POINTER_MOTION_MASK | GDK_PROPERTY_CHANGE_MASK |
+                     GDK_FOCUS_CHANGE_MASK;
 
 /* utility functions */
 static bool is_mouse_in_window(GdkWindow* aWindow, gdouble aMouseX,