In this particular case, we have custom RadButtonElements placed in the title bar of the form. We have subscribed to the click event on each button. In the click event handlers, we are showing file dialogs. When clicking one time to show a dialog and the mouse leaves the title bar bounds, this triggers the click event twice, thus opening another dialog.

As a workaround, we could use the MouseDown event instead or raise a flag in the click event handler.