I'm not registered to create a bug ticket.

Posting a bug in SourceForge tracker is still the best place. I hope you'll understand that managing all the bugs at the same place is easier for me and users who follow bug fixes.

I'm aware of the bug you reported. I'm not sure I'll fix it soon because there's a simple workaround: instead of double-clicking in the room, draw it corner by corner, with at a moment a line that will go from an "outer" corner to an "inner" corner. Hope you can understand what I mean.