Deleting in Insert mode makes program unresponsive

When I deleted 20 bars’ worth of simple piano music from this project, with Insert mode on, Dorico became unresponsive for a long time (maybe 10 minutes). The cursor turned into the wristwatch icon, which I have been seeing quite a lot of recently. Nothing happened except that at one point all the bar numbers disappeared. Eventually I decided to create a diagnostics report. This also took a long time (at least 20 minutes, I think), but once it was done the project had become usable again. Is this normal?

The VST I was using was again Synthogy Ivory II, but this time it is the latest version, and anyway playback was stopped when this happened.

The contents of the project were originally imported from a MIDI file, if that’s relevant.
J C Bach op 5 #2 minuet.dorico (1.3 MB)
Dorico (767.8 KB)

I suspect (though I’m not sure) that what you’re experiencing here is the same issue that affects some other editing operations, such as double/halve note values. We’re on the tail of that problem and I’m reasonably confident we’ll have a fix for it in the next update.