#1265 Lock dimensions of items down so without unlocking they cannot be changed

[Mary Lark]

Please include a lock for dimensions. I cannot tell you the number of times I've drawn a wall, or a segment of a wall, window, or door ... only to accidentally bump it and have the dimensions change!

For instance, to use the Staircase creator plugin it has to go below the walls. So I have to move the walls out of the way and blam! The dimensions are lost because I touched the wrong part of the wall.