I'm still not sure how to reproduce it, it's just trial and error. I just switched to Firefox to other running applications and back again, opened the HUD every now and then, and most of the time there's no crash. And then suddenly it happens. I hope the stack trace can help you.
It also seems that the crash can happen when Firefox doesn't have the focus while opening the HUD.
Here's a stack trace I created following the instructions from https:/ /wiki.ubuntu. com/MozillaTeam /Bugs#Run_ Firefox_ in_a_Debugger
I'm still not sure how to reproduce it, it's just trial and error. I just switched to Firefox to other running applications and back again, opened the HUD every now and then, and most of the time there's no crash. And then suddenly it happens. I hope the stack trace can help you.
It also seems that the crash can happen when Firefox doesn't have the focus while opening the HUD.