In the File Status view, the pane that shows the list of files can collapse to zero width and be hard/impossible to expand.

In community discussions about this bug, some people have suggested suboptimal ways of re-expanding the pane, but these are unintuitive and unreliable (none have worked for me, for instance).

I am marking the priority as high because the bug makes viewing diffs in the working branch impossible (core functionality), the issue has been present since May, and multiple people have been affected.

Related community discussion:

https://community.atlassian.com/t5/Sourcetree-questions/File-Status-only-showing-diff/qaq-p/2707933

https://community.atlassian.com/t5/Sourcetree-questions/File-status-menu-doesn-t-show-up-list-of-files/qaq-p/2711411