Limitations

Elevated applications

A program running as administrator cannot be touched by one that is not. To group an elevated application, PerchBar has to be elevated too: tray icon → Restart as administrator.

UWP windows

Some Store applications draw their windows through a shared Windows host. Their button comes from the app package and ignores anything PerchBar writes, so those windows cannot be grouped. Calculator is one.

This is not "Store apps do not work": a packaged application with an ordinary window groups perfectly well — Windows Terminal is a Store app and works. PerchBar tests the window rather than guessing from the path, and warns you at the moment you add one it cannot group.

Grouping needs PerchBar running

An identity lasts as long as the window, so windows already grouped stay grouped — but a window opened while PerchBar is not running is not claimed. Turn on Start with Windows, or use Group running windows now to catch up.

Pinning is by hand

Windows does not let an application pin anything to the taskbar. PerchBar writes the shortcut; you right-click it and pin it. See Pinning a group to the taskbar.