The crash is caused by Tagging for Windows creating dialogs with null dialog-procs.
I may be wrong but, as far as I'm aware, doing that isn't useful or allowed according to the API docs. I'm surprised the OS doesn't fail the creation request, but apparently it is at least tolerated by the OS, whether or not it's actually allowed.
Maybe there's a valid reason for their code doing this, or maybe it's unintentional but hasn't been noticed, as it doesn't usually crash. I can't say.
We've added a check for this and it seems to fix the crashes, at least.