--- GdkQuartzWindow.c.orig	2016-02-20 13:09:16.290642581 -0500
+++ GdkQuartzWindow.c	2016-02-20 13:10:39.886709040 -0500
@@ -24,6 +24,14 @@
 
 @implementation GdkQuartzWindow
 
+- (void)windowWillClose:(NSNotification*)notification
+{
+  // Clears the delegate when window is going to be closed; since EL
+  // Capitan it is possible that the methods of delegate would get
+  // called after the window has been closed.
+  [self setDelegate:nil];
+}
+
 -(BOOL)windowShouldClose:(id)sender
 {
   GdkWindow *window = [[self contentView] gdkWindow];
--- GdkQuartzView.c.orig	2016-02-20 13:09:26.641403172 -0500
+++ GdkQuartzView.c	2016-02-20 13:12:45.434805163 -0500
@@ -684,7 +684,7 @@
   GdkWindowImplQuartz *impl = GDK_WINDOW_IMPL_QUARTZ (private->impl);
   NSRect rect;
 
-  if (!impl->toplevel)
+  if (!impl || !impl->toplevel)
     return;
 
   if (trackingRect)