ref: 340c300c1dd38f3a5efe4d03bea27973aa71c563
parent: ed63f9c50efeb26f3decade7dc50c7b0efa008ae
author: Simon Tatham <anakin@pobox.com>
date: Thu Feb 2 02:18:14 EST 2012
David Nickerson reports that it's possible to lay a line over a 'no line here' cross mark by dragging, and furthermore, that doing so puts that grid edge into a stuck state that no UI action short of undo can get it back out of. Fix drags to stop at crosses, and fix execute_move to fault any move string that nonetheless somehow managed to try to set a line over a cross without explicitly tagging it 'R'. [originally from svn r9400]