Better version of 817fccb3e5, the visibility should not depend
on the number of items in the dialog, but its requested height
vs screen height.
The main use-case is to not show the scroll-bar if the dialog has only
a few rows. Then again if the scrollbar is visible, the dialog
should not shrink below a reasonable min. height.
Copyright-holder and year information is extracted from git log.
git history begins in 2005. So (C) from 1998..2005 is lost. Also some
(C) assignment of commits where the committer didn't use --author.