Regression: Always prevent default behaviour of main menu click event

This is breaking our tests
We use the mousedown event but do not prevent the default click
event.
Follow up to  I9b6ae95b6145eb8c9cfe2868ab49112b77ee1b2a

Change-Id: I16bbc9b6efdcda1afb6f83ccd4ab3a74e481cfbb
Merge "Regression: Always prevent default behaviour of main menu click event"