After installing build 10074, the behavior of Start 10/Windows 10 menus changed.
I am running Windows 10 from VMWare with a dual monitor setup.
I have the Start button on the main display only (as configured).
When I click the Start button the Start 10 menu appears as expected.
When I select the Windows 10 menu option from Start 10, the Windows 10 menu appears on the secondary screen only.
When I Ctrl+Start, the Windows 10 menu appears on the secondary screen as well.
I upgraded to the .56 beta of Start 10 to see if it fixed the behavior. It did not.
I uninstalled Start 10 and reinstalled with no luck either.