After dragging the main menu, the widget add/edit pop-up can be hidden under the main menu.

Steps to reproduce:

1. Open a dashboard.
2. Collapse the main menu and then expand it back.
3. Add a new widget or edit an existing one.
4. Drag the widget configuration pop-up under the main menu.

Result:
The widget add/edit configuration pop-up can be completely hidden under the main menu.

Expected:
The widget add/edit configuration pop-up should always remain at least partially visible.