track if the mouse was released after menu open

Make sure the menu isn't closed by the mouse up that is directly followed by the mouse down that opened the menu.

AppKit/CPMenu/_CPMenuManager.j

@@ -11,6 +11,7 @@ var STICKY_TIME_INTERVAL            = 500,
 @implementation _CPMenuManager: CPObject
 {
     CPTimeInterval      _startTime;
+    BOOL                _hasMouseGoneUpAfterStartedTracking;
     int                 _scrollingState;
     CGPoint             _lastGlobalLocation;
 
@@ -87,6 +88,8 @@ var STICKY_TIME_INTERVAL            = 500,
             return [self trackMenuBarButtonEvent:anEvent];
     }
 
+    _hasMouseGoneUpAfterStartedTracking = NO;
+
     [self trackEvent:anEvent];
 }
 
@@ -221,8 +224,13 @@ var STICKY_TIME_INTERVAL            = 500,
                     [CPEvent startPeriodicEventsAfterDelay:0.0 withPeriod:0.04];
             }
         }
-        else if (type === CPLeftMouseUp && ([anEvent timestamp] - _startTime > (STICKY_TIME_INTERVAL + [activeMenu numberOfItems] * 5)))
-            [trackingMenu cancelTracking];
+        else if (type === CPLeftMouseUp)
+        {
+            if (_hasMouseGoneUpAfterStartedTracking)
+                [trackingMenu cancelTracking];
+            else
+                _hasMouseGoneUpAfterStartedTracking = YES;
+        }
     }
 
     // Prevent previous selected menu items from opening by stopping the timer if a