OS X: Closing a window confuses its mouse button state

If a mouse is clicked on a push button and moved to child widget, Child widget receives mouse clicked event.

Attached example reproduces it.
Steps:
Run the example and click on push button ( a new widget will popup)
Close the new widget and re click on push button to see the pop up again
now move the mouse over the new poped up widget and experience it gets mouse click event.