How to fit menu in all resolutions

I made an main menu and when you change the resolution the menu doesn’t anymore fit the screen, How can i make it to fit the screen? Or is the best option to just make a new menu for all the resolutions

I know this answer is late, but one way is to use the Anchor options for the widget.

If you select the anchor option in the screenshot and set 0 for all of the offsets, then the widget should span any screen.