Dialog boxes stuck in Mac IDE

Hah. I made a mistake: Three projects, A, B and C open in the IDE. In project A I started to select a file for the “Copy File” build step. In open dialog I noticed a folder in sidebar that I decided to remove while I was at it. So I dragged it away from the sidebar. Instead of disappearing, it was accepted by project B underneath. And B presented the “Resolve the following issues” sheet. So, two projects open, with modal interaction dialogs blocking access to them.
The interesting part is that both dialogs refuse to go away. Both dialogs hilight mouse and keyboard shortcut hits, but Close/Cancel-buttons do nothing. I can navigate file system in the open dialog, just no way to dismiss it.
So I have no way to save projects’ changes to any of the projects.
I’m only interested in changes in project A. I wonder if there was a way to kill B. Probably not. Guess I’ll force quit Xojo for the night.