"Stop Tracking" doesn't do anything

1. Right click on a tracked file
2. Select `Stop Tracking`

Expected result: the file becomes untracked and a deletion action is added to the staging area

Actual result: nothing happens

Notes:

• my Atlassian Questions question - https://answers.atlassian.com/questions/39785117/comments/39993779 - got a response from another user, "The issue seems to be that the cancel and Okay button functionality is switched up for that option. Hitting cancel actually made it stop tracking the file(s) for me". I haven't checked this myself as I went back to 1.8.3.0.