Are you using the latest version of VS 2017 (15.9.4)?
End of programcsharp's quote
It was 15.9.2 but updating did not change my result.
The only way to get it to properly go into VS without auto groupy is to start dragging the tab, let it go into groupy, break it out of the group, then carefully click the titlebar (vs the tab) and drag it in.
End of programcsharp's quote
Ok, you are doing something a bit different, busting out actual files from VS and grouping. I am not certain how Groupy sees the detached file but I suspect it is like Outlook when dragging out emails, they just look different to the Groupy.
If you initiate actual instance of VS, it should perform like shown in my video.
Sean Drohan
Stardock Support Manager