We all know the good old Emacs mode-line you got under every window. Since the beginning (a long time ago), it starts and ends with dashes. I've proposed a patch to remove them.

Before:

Screenshot of Emacs with dashes in the mode line

After:

Screenshot of Emacs without dashes in the mode line

This has been merged in Emacs 24. You won't see any more ugly dashes in graphical mode.