To be honest I don't know if it's a but or an enhancement or even if it's possible on Windows:

Windows don't take into account cases which make changing file names cases a not-a-change.
The problem is that into a git or mercurial repository, it is a change (if no related extension is active).

Currently SourceTree will not see these kind of changes.
Would it be possible for the windows version of SourceTree to perform a check on changes of case? Or maybe it's dependent on git?
Or maybe provide a way to do the filename change from SourceTree or to declare that these files case should be checked?