ref: cf0b0b747b4ce389b07ccd6e29a50074a940ac93
parent: 682ea218de892122615f8aff7338306198fe56f4
author: Simon Tatham <anakin@pobox.com>
date: Thu Mar 1 02:32:35 EST 2007
Bound edge thicknesses below so that they're always thicker than the grid lines. [originally from svn r7349]