Wow, only great responses this time, impressed, thanks so much to everyone!
As offered, and requested by @slbaumgartner and @Geo I try to insert the file here. Despite my risk that “everyone” might have a laugh at us aka “what, you didn’t notice WHY it suddenly fails? You stupid user you!”…
@colin 's hint (“The customer was getting a bit upset about it, but managed to track down the problem to FredoGuides”) is interesting as it is along one of my own ideas that maybe an accidental keystroke “wrongly” started some extension. However, Colin’s case description is entirely different, but yes it could be another such issue, why not.
@DanRathbun: “Is it outside the SketchUp applications window ?”, Sorry, with “OUTSIDE the model” I meant inside the application window, just outside our actual model context.
When/If you see the file: the weird new dotted rectangle is the one you see LEFT. (the components briefly set aside on the right were on purpose).
“ESC key” no change
“mouse” is great
“update history” we would NEVER allow silent background updates, nor should you
" reboot the computer to refresh all memory" - this one is interesting, we didn’t do THAT because it stops (gosh) all other apps running and needed. ALSO because: can “memory actually get corrupted” in such way that still any other model works well, and ONLY the weird one does not, suddenly?
I am not geek enough to know, only you are, Dan.
My guess: no. Then NO model would work anymore.
Now here’s the promised file, as said, it’s a model from 3DWH, just changed a lot already.
Floor plan II.skp (610.1 KB)