Dual Monitors in full screen doesn't focus when dropping windows into other screen

[danf84]

When in Full Screen mode and Guest OS having 2 Virtual Monitors, moving 1 window to another screen requires an additional click to have the focus on what should already have a focus (i.e. to drag the window back to the other monitor, I'd need another click to focus the "window/screen/monitor" then I can click+drag. For completeness, I think this is a "minor" fault. Fixing this will make it as seamless as a real dual monitor setup!