menubutton: Fix possible button/popover state inconsistences
menubutton: Fix possible button/popover state inconsistences

While a popover is hiding, the modal grab is already gone and the toggle
button is clickable again, but clicking again at that time will result in
gtk_widget_show() trying to show an already shown widget (although fading
out and hidden soon) and the toggle button activated.

So let the menubutton set the active status only if the menu/popover
widget wasn't already shown, and ensure this doesn't get triggered by
double/triple button press events.

davidgumberg/gtk,Adamovskiy/gtk,jadahl/gtk,chergert/gtk,Adamovskiy/gtk,Lyude/gtk-,ahodesuka/gtk,chergert/gtk,davidgumberg/gtk,grubersjoe/adwaita,alexlarsson/gtk,Adamovskiy/gtk,alexlarsson/gtk,chergert/gtk,Adamovskiy/gtk,jadahl/gtk,Adamovskiy/gtk,chergert/gtk,chergert/gtk,jigpu/gtk,ahodesuka/gtk,grubersjoe/adwaita,davidgumberg/gtk,davidgumberg/gtk,ahodesuka/gtk,Adamovskiy/gtk,alexlarsson/gtk,Lyude/gtk-,Lyude/gtk-,ahodesuka/gtk,chergert/gtk,ahodesuka/gtk,ahodesuka/gtk,alexlarsson/gtk,Lyude/gtk-,Adamovskiy/gtk,davidgumberg/gtk,jigpu/gtk,Lyude/gtk-,ahodesuka/gtk,Lyude/gtk-,jadahl/gtk,chergert/gtk,jadahl/gtk,ahodesuka/gtk,Lyude/gtk-,jigpu/gtk,grubersjoe/adwaita,jadahl/gtk,grubersjoe/adwaita,jigpu/gtk,alexlarsson/gtk,jigpu/gtk,alexlarsson/gtk,Adamovskiy/gtk,grubersjoe/adwaita,grubersjoe/adwaita,jadahl/gtk,jigpu/gtk,jigpu/gtk,chergert/gtk,davidgumberg/gtk,jadahl/gtk,jadahl/gtk,Lyude/gtk-,davidgumberg/gtk,davidgumberg/gtk,alexlarsson/gtk,alexlarsson/gtk,grubersjoe/adwaita,grubersjoe/adwaita,jigpu/gtk