Incorrect layout of git show object

When clicking on a revision in a git diff, the source is shown in a small pane at the top, while most of the space is wasted in an unused diff pane showing two panes with the text "No difference."

Workaround: Pull down the useless diff pane with the spacer every time.

Expected: Best would be not to show the unused diff pane at all. Otherwise the spacer position should be persistent at least.