Hello Patrick,

This is a bug that occurs in some situations, one of them is when a wall overlaps another wall. I fixed it in your plan, so it should be gone now, is it? Next time, make sure you don’t have any walls overlapping eachother. Check this by moving with your mouse over a wall. It turns blue. If there is a corner point (a white dot) somewhere in the middle of the wall you have an overlap. get rid of it by splitting the wall next to the white dot, and dragging the split point to the white dot. If a wall overlaps more than one wall you’ll have to repeat this action.

good luck,

Nico
Floorplanner Team