I wasn't trying to bust the file out, just take it inside VS and split it to two panes, but for some reason Groupy was grabbing the file and going to auto-group instead of letting VS's split pane stuff work.
I was able to fix this by toggling the exclude. I grouped and then unchecked "automatically exclude" and then closed out VS. Then opened VS and grouped and re-checked "automatically exclude". Now it is correctly letting VS do its split pane stuff instead of immediately grouping it in like my video. Normally when splitting to two panes, VS doesn't create an additional window, so Groupy must have been getting in there and splitting it out somehow.
After toggling the setting, it even works with "automatically exclude" disabled -- it doesn't grab the file immediately like in my video but only if I drag to title bar. Does toggling that reset some other setting in Groupy?
Is there any way to do a "never group" vs "automatically exclude"? Some things like VS you never want to Groupy because they have their own window management.