Little bar on top when stacking windows one on top of another

[MoutonBinoclard]

Hello everyone, when i put a window on top of another, i got this banner. I don't understand the need for it. Can someone explain me if I can get rid of it or just why is it important ?
Thanks

[coffeeneed]

Same for me. I love FancyVM, but it just seems like another taskbar to me. Is it possible to disable it?

[veselink1]

The panel indicates what layout is applied to a group of windows.

Normally, the top level panel for a desktop is horizontal panel. The top level panel does not have this bar visible, but any other nested panels do. It is possible to nest a horizontal panel inside another horizontal panel, in which case, I expect you will see something like in the screenshot.