W11 
Coming from Groupy v1, just upgraded to Groupy v2. Several things I noticed:
1. CPU load of GroupyCtrl increases whenever the mouse is moved, even more so when the mouse uses a higher polling rate (kike 1 kHz). This also happens when the "hover over title bar" option is disabled and no Groupy group is currently on-screen.
Mouse moving:

Mouse not moving:

Furthermore Groupy's CPU load increases over time. Here is what it looks like after a fresh start:

2. "Show only one combined button" produces multiple problems:
- Not properly restoring window(s) when the taskbar icon is pressed multiple times. This behaves erratic, sometime a window group is shown as empty and cannot be selected from the taskbar icon, sometimes all windows are resized to minimum.

And when this option is chosen then it breaks the other "Show only active window" option until the window group / application is restarted.
3. Wrong application placement below the Groupy bar. This does not happen in Groupy v1:
When Groupy is used with PDF X-Change Editor then it places the application window too high below Groupy's bar. This is fixed by causing redrawing of the whole windows group, like minimize/restore/maximize or switching tabs "above vs. integrated" options (X-Change always uses "above").
vs. 
4. Locking a group still seems to interfere with loading saved groups!? That's been a thing for many years already.
I also wonder if there is no way for Groupy to restore its tab order so that I don't have to move tabs manually every time I load multiple windows (in arbitrary load order)?