Unfortunately the Visual Basic 6 IDE is 19 years old and isn't even officially able to install on 64 bit Windows 10.  It does things a little 'differently' probably as leftovers from its 16 bit days.

For example you may notice when you minimize it you see solid black paint where the window shadows would be briefly.

We are looking into this report though as by pure chance VB6 was on my dev box and hopefully future versions may support it better.  That said be aware that Groupy 1.21 which is due for release very soon may not allow VB6 to group at all so you may want to stick with 1.2 until we update this thread saying a release addresses this.

Currently we can fix the minimize issue and the extra taskbar buttons that get created when you switch tabs, but there is a problem with switching between tabs from the taskbar when one is minimized.  It may be that the way it works simply makes it incompatible with grouping though, it really is an unusual app.