On startup UEStudio doesn't check that open files (from the previous session) are part of a git repo (same may be true for other source control). The only method I've found for the status to be refreshed is to use the File Explorer tab.

Whilst the status is being refreshed as part of opening the tab the UI and Window is locked, I guess it's synchronous wait. This lock lasts for a number of minutes regardless of the number of files open. Whilst the Window is locked the user can't navigate away from UE without killing the process.

This has been a problem, for me, for a very long time. I don't use Project files if that's relevant.