Feature request: option to disable current runtime

[Patola]

It seems that once I make a runtime active, the GUI doesn't offer an option to inactivate it? I had to remove the link in ~/.config/openxr/1/ by hand.

[rpavlik]

yeah I hit the desire to do this recently too. Not sure when I'll have time to work on it, this would be a nice PR if someone wanted to contribute.