window needs to be "realized" only after atoms getting set

works now.

atomPropertyGDKx11.hs

@@ -30,7 +30,7 @@ main = do
       , #decorated := False
       ]
 
-    #realize win
+   
     Gtk.windowSetDefaultSize win 400 100
     
 
@@ -66,7 +66,8 @@ main = do
         pure ()  -- <--- important: SourceFunc expects IO Bool
 
       return False  -- just indicate mainContextInvokeFull call succeeded
-      
+
+    #realize win  
     Gtk.widgetShow win
       
   void $ applicationRun app Nothing