It would be awesome if you could create a new room directly from the properties window. I could imagine a feature like this:

• There are buttons ordered in a 3x3 grid for each direction, N, NE, E, and so on
• According to the button you've clicked a new room gets created next to the current one, and the properties window is showing the properties for the new room.
• The changes you've made for the previous room are getting saved the moment you've clicked the button (like pressing the ok button)
• The room gets automatically connected to the previous room, there is one grid space between the old room and the new room