New issue 240: Windows Alt+Tab https://bitbucket.org/valentinateam/valentina/issue/240/windows-alt-tab
Felix Ulber:
And yet another one 
On Windows us use Alt+Tab to quickly change between running Applications. Thats an extremely convenient shortcut I could not live without (and that has fortunately adopted by at least KDE on Linux
On Windows 7 I experience a strange thing: most of the time, but not everytime, Valentina just does not appear in the switching list, though it is open and visible in the task bar. Didn’t experience that on Windows 8.1 yet.