EDIT – I have made some updates to the QuickCurve function to do more error checking and hopefully make this workable. It’s not a permanent fix, but it should stop the error happening for now. Please re-download when you have a chance.
OK. I have implemented a much more sophisticated solution to the QuickCurve issue and updated the download link (BETA2).
This should now work as intended without hiding any objects. I see my error!
When adding points, everything else, except adding points in the viewport, is death. Clicking around everywhere I encountered this error message, doesn’t mean anything to me.
Should also now be fixed in latest download. Thanks.