[Feature] Only allow single window

[Lxtharia]

When setting a shortcut in my desktop for opening glimpse (running the glimpse command) I would like to toggle the bar with this shortcut.

Therefor, running glimpse should close an existing glimpse window instead of opening a new one.

[NureSytnykYehor]

+1, it will be wery useful.

But for now you can use the next workaround

killall glimpse || glimpse