Split button's menu is visible always when the user skips to a different application with Alt+Tab. It is also visible when qds is closed.

Steps to reproduce:

• Open any project in QDS
• Click open menu and move mouse left, eg. hover play image 
• Alt+Tab and skip to some other application. Then close QDS.

Actual: Menu will be visible all the time, like it is detached from main application.

Expected: Menu should not be visible.