In the "Staged files" and "Unstaged files" lists you cannot deselect a file without selecting a different file. So if you have all files selected it is impossible to deselect any of the files. Why doesn't this work the same way as any other file selection lists / dialogs in every other program, i.e. when multiple items are selected then clicking on a selected item will deselect all other files, and ctrl-clicking will deselect the clicked file?

Additionally clicking on the very odd stage/unstage checkbox does not work when multiple files are selected so you have to bring up the context menu to stage / unstage or do it one by one (if you haven't selected all the files that is).