diff --git a/Window/MainWindow.m b/Window/MainWindow.m
index ebb16f8c6..16fd36b86 100644
--- a/Window/MainWindow.m
+++ b/Window/MainWindow.m
@@ -18,6 +18,7 @@
 	{
 		[self setExcludedFromWindowsMenu:YES];
 		[self setContentBorderThickness:24.0 forEdge:NSMinYEdge];
+        [self setCollectionBehavior:NSWindowCollectionBehaviorFullScreenPrimary];
 	}
 	
 	return self;
diff --git a/Window/MiniWindow.m b/Window/MiniWindow.m
index 44211abc2..5840c8c9d 100644
--- a/Window/MiniWindow.m
+++ b/Window/MiniWindow.m
@@ -18,6 +18,7 @@
 	{
 		[self setShowsResizeIndicator:NO];
 		[self setExcludedFromWindowsMenu:YES];
+        [self setCollectionBehavior:NSWindowCollectionBehaviorFullScreenAuxiliary];
 	}
 	
 	return self;