The crash happens in nsMenuItem::UncheckSiblings(), and is caused by trying to access the name attribute of an XML element that doesn't have a name (in this case, a comment: https://gitlab.com/enigmail/enigmail/-/blob/master/ui/content/enigmailMsgComposeOverlay.xul#L72).
The crash happens in nsMenuItem: :UncheckSibling s(), and is caused by trying to access the name attribute of an XML element that doesn't have a name (in this case, a comment: https:/ /gitlab. com/enigmail/ enigmail/ -/blob/ master/ ui/content/ enigmailMsgComp oseOverlay. xul#L72).