Move the Open Shell menu

[dremin]

Open Shell Menu doesn't handle WinKey invocation well on secondary monitors. This PR adds logic to move the Open Shell Menu to the correct position based on monitor and the screen edge of the taskbar, only when the start button is enabled for multiple monitors.

Open Shell Menu does have code that supports receiving programmatic activation via window message, but it doesn't use WM_COPYDATA so we cannot send the necessary struct cross-process.

@xoascf - This is similar to what you initially wrote for the modern calendar flyout. There is a brief flicker before it moves, but I think it is better than not moving it at all. What do you think?

[xoascf]

@xoascf - This is similar to what you initially wrote for the modern calendar flyout. There is a brief flicker before it moves, but I think it is better than not moving it at all. What do you think?

On Windows 10, it also flickers when you try to reopen the Modern Start menu after closing it with the taskbar in a different location:

By the way, there should be a loop to move both the classic Start menu (with "Desktop User Picture") when it is open too, for consistency. I remember being able to do this in the past, years ago, I think this used to work: https://www.codeproject.com/Questions/213786/Show-StartMenu-on-custom-position-in-Csharp (but unfortunately the link is dead for now), also asked the SAB developer recently, but no luck:

Just today I used AutoHotKey and it worked for me!: https://www.autohotkey.com/board/topic/103426-winmove-wont-stick-moving-start-menu/

[dremin]

On Windows 10, it also flickers when you try to reopen the Modern Start menu after closing it with the taskbar in a different location

Heh, good old MS keeping standards low!

By the way, there should be a loop to move both the classic Start menu (with "Desktop User Picture") when it is open too, for consistency. I remember being able to do this in the past, years ago, I think this used to work: https://www.codeproject.com/Questions/213786/Show-StartMenu-on-custom-position-in-Csharp (but unfortunately the link is dead for now), also asked the SAB developer recently, but no luck:

Just today I used AutoHotKey and it worked for me!: https://www.autohotkey.com/board/topic/103426-winmove-wont-stick-moving-start-menu/

When I move the Windows 7 menu, the menu itself moves fine but the hover effects and submenus get really glitchy for me.