It works! 
No idea how cames. Thanks a lot @otter2 for your solution and help. Cool to have met you here.
Just a note: Maybe I am wrong here. If we have for this Super L, let us say, with clicking the Windows Symbol for opening that (Qubes Application Menu), so there might be hard to deal with switching tabs with the keyboard. 
Fortunately not at all. It is working well with arrow keys
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After discussion with @adw on Github Issue, the program turned to be like this:
Missing O in Bottom text will be added.
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Awesome!
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