We updated the Firefox based control as part of the development for Paratext 9.0 and this has led to some problems with crashing - seems to happen most frequently when editing notes.
We have some recent fixes that should help with this, but those aren’t in the latest Paratext 9.1 beta (the change is too big to do for Paratext 9.0).
We are starting to test the release candidate for Paratext 9.1, so will hopefully make this available fairly soon.
John+Wickberg
Paratext Support