diff --git a/AppKit/CPWindow/CPWindow.j b/AppKit/CPWindow/CPWindow.j
index 9e7eac0dc..d010871ed 100644
--- a/AppKit/CPWindow/CPWindow.j
+++ b/AppKit/CPWindow/CPWindow.j
@@ -1368,7 +1368,15 @@ CPTexturedBackgroundWindowMask
     var size = [self frame].size,
         containerSize = [CPPlatform isBrowser] ? [_platformWindow contentBounds].size : [[self screen] visibleFrame].size;
 
-    [self setFrameOrigin:CGPointMake((containerSize.width - size.width) / 2.0, (containerSize.height - size.height) / 2.0)];
+    var origin = CGPointMake((containerSize.width - size.width) / 2.0, (containerSize.height - size.height) / 2.0);
+
+    if (origin.x < 0.0)
+        origin.x = 0.0;
+
+    if (origin.y < 0.0)
+        origin.y = 0.0;
+
+    [self setFrameOrigin:origin];
 }
 
 /*!