Some time ago I pressed a weird key combination that seemed to add a margin to the top and bottom of active application window (in this case, iTerm2). See screenshot below:
It doesn't happen on any other apps. Just this one, so it is like the OS or Window manager has remembered this setting for this specific app.
I have no idea what the key combination was or how to remove this margin. It's very infuriating.
I use Spectacle to resize/re-position windows so I suspected it may be related to this app but it has no mention of being able to create window margins.
Any ideas? Perhaps someone knows where the OS stores application-specific window properties?