I have my 7 rooms loaded. Editing room 1, I put in the edges, then walkable areas would not let me put in the areas. Line draw and fill do not work. I can put in one line but when I release the mouse button it disappears. Pressing fill and touching the middle of area does not work either.
Check what color you're drawing with. Color 0 (black) is used for erasing..make sure you're not using that.