gitk: Un-hide selection in areas with non-default background color
The recently introduced background for the tags that highlight
added and removed text takes precedence over the background color
of the selection. But selected text is more important than the
highlighted text. Make the highlighting tags the lowest priority.
The same argument holds for the file separator and the highlight
of search results. Therefore, make them also low-priority. But
search results are a bit more important; therefore, keep them
above the other tags.
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>