Fill tool has been deprecated. You should be using the lasso tool with color lasso on to fill.
Room width and room height size
You now need to choose room width size before choosing room height size if you want it to work. The crash is fixed however if you pick room height in the very beginning it will just make the room width size to 1.
Prevented crash
Prevented a crash with room width and room height.
Mini canvas reworked
Mini canvas has been reworked to match the size of the main canvas, but the size is divided by 10.