diff --git a/src/Fl_cocoa.mm b/src/Fl_cocoa.mm
index be07b09fb..ae2958861 100644
--- a/src/Fl_cocoa.mm
+++ b/src/Fl_cocoa.mm
@@ -674,6 +674,9 @@ void Fl::remove_timeout(Fl_Timeout_Handler cb, void* data)
 + (void)concatEtext:(NSString*)aString;
 - (BOOL)process_keydown:(NSEvent*)theEvent;
 - (id)initWithFrame:(NSRect)frameRect;
+- (void)viewDidMoveToWindow;
+- (void)setFrameSize:(NSSize)newSize;
+- (void)updateWindowSize;
 - (void)drawRect:(NSRect)rect;
 - (BOOL)acceptsFirstResponder;
 - (BOOL)acceptsFirstMouse:(NSEvent*)theEvent;
@@ -1260,7 +1263,6 @@ static FLTextView *fltextview_instance = nil;
 + (void)initialize;
 + (FLWindowDelegate*)singleInstance;
 - (void)windowDidMove:(NSNotification *)notif;
-- (void)view_did_resize:(NSNotification *)notif;
 - (void)windowDidResignKey:(NSNotification *)notif;
 - (void)windowDidBecomeKey:(NSNotification *)notif;
 - (void)windowDidBecomeMain:(NSNotification *)notif;
@@ -1448,29 +1450,6 @@ static FLWindowDelegate *flwindowdelegate_instance = nil;
   }
   fl_unlock_function();
 }
-- (void)view_did_resize:(NSNotification *)notif
-{
-  if (![[notif object] isKindOfClass:[FLView class]]) return;
-  FLView *view = (FLView*)[notif object];
-  FLWindow *nsw = (FLWindow*)[view window];
-  if (!nsw || ![nsw getFl_Window]) return;
-  fl_lock_function();
-  Fl_Window *window = [nsw getFl_Window];
-  int X, Y;
-  CocoatoFLTK(window, X, Y);
-  NSRect r = [view frame];
-  Fl_X::i(window)->in_windowDidResize(1);
-  window->resize(X, Y, r.size.width, r.size.height);
-  Fl_X::i(window)->in_windowDidResize(0);
-  update_e_xy_and_e_xy_root(nsw);
-#if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_14
-  if (views_use_CA && !window->as_gl_window()) {
-    [view reset_aux_bitmap];
-    window->redraw();
-  }
-#endif
-  fl_unlock_function();
-}
 - (void)windowDidResignKey:(NSNotification *)notif
 {
   fl_lock_function();
@@ -1917,10 +1896,6 @@ void fl_open_display() {
 					     selector:@selector(anyWindowWillClose:) 
 						 name:NSWindowWillCloseNotification 
 					       object:nil];
-    [[NSNotificationCenter defaultCenter] addObserver:[FLWindowDelegate singleInstance]
-                                             selector:@selector(view_did_resize:)
-                                                 name:NSViewFrameDidChangeNotification
-                                               object:nil];
     if (![NSThread isMultiThreaded]) {
       // With old OS X versions, it is necessary to create one thread for secondary pthreads to be
       // allowed to use cocoa, especially to create an NSAutoreleasePool.
@@ -2414,6 +2389,39 @@ static FLTextInputContext* fltextinputcontext_instance = nil;
   return self;
 }
 
+- (void)viewDidMoveToWindow
+{
+  [self updateWindowSize];
+}
+
+- (void)setFrameSize:(NSSize)newSize
+{
+  [super setFrameSize:newSize];
+  [self updateWindowSize];
+}
+
+- (void)updateWindowSize
+{
+  FLWindow *nsw = (FLWindow*)[self window];
+  if (!nsw || ![nsw getFl_Window]) return;
+  fl_lock_function();
+  Fl_Window *window = [nsw getFl_Window];
+  int X, Y;
+  CocoatoFLTK(window, X, Y);
+  NSRect r = [self frame];
+  Fl_X::i(window)->in_windowDidResize(1);
+  window->resize(X, Y, r.size.width, r.size.height);
+  Fl_X::i(window)->in_windowDidResize(0);
+  update_e_xy_and_e_xy_root(nsw);
+#if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_14
+  if (views_use_CA && !window->as_gl_window()) {
+    [self reset_aux_bitmap];
+    window->redraw();
+  }
+#endif
+  fl_unlock_function();
+}
+
 /* Used by all GL or non-GL windows.
  * Gets called when a window is created, resized, or moved between retina and non-retina displays.
  * For non-GL windows, also called by Fl_X::flush() because of the display message sent to the view.