Remove the auto-scan in the Add Non-Steam Game window
When I open said window, it scans my computer for a good half minute and doesn't let me click the Browse button. After that, my game is never in the scan list anyway, so I click Browse and find it as I had intended to do from the beginning.

Either let us browse while the scan is running, or let the user start the scan manually so we may choose to not do it.

Understand that I'm not exaggerating when I say this: I have never, ever benefitted from the auto-scan feature, except that I use the downtime as a water break.