In previous versions of the SourceTree user could step on a file and the context menu gave an opportunity to open Windows directory with this very file highlighted.

In the current version we have "Explorer" menu icon/option on top of the screen, which delivers the same functionality.

But it is counter-intuitive to click on icon on top to get action applied to file highlighted closer to the bottom of the screen in "File Status", "Log/History" or "Search" panels.

It is more reasonable to expect that icons on top will act on entire highlighted branch.
And all of the icons except "Explorer" act on an active branch or on entire repository.

Please, plug "explorer" functionality to open directory for particular file into a right-click context menu for highlighted file.

It also makes sense to change the current "Explorer" icon action to something applied to repository. Maybe open the topmost directory of the repository, where ".git" sub-directory is located.