New
- A folder as a group. In the group editor, pick What is in a folder and choose any folder, or one of the Windows places: All Control Panel Items, Windows Tools, This PC, All apps, Desktop, Downloads and a few more. The panel lists what is in it every time it opens, so it is always current. Folders inside it that hold something open beside the panel like a submenu, with an arrow, and everything has its own Windows right-click menu. (#9)
- A whole taskbar from one group. Click Pin to taskbar on a group that holds other groups and the app offers to pin all of them, one after another, in the group's order, with a taskbar separator for every separator line in it. Windows doesn't let apps pin anything by themselves, so each pin is still your right-click: the app keeps the next shortcut selected in File Explorer and moves on as soon as you pin it. (#8)
- Groups inside a group now show an arrow in the panel, as they open beside it.
Windows 10
- The steps to pin a group match the Windows 10 right-click menu, which has Pin to taskbar right there, without Show more options.
- The panel draws its border square, like every other window on Windows 10.
- Open on hover also recognises a pinned group on a taskbar that reports its buttons by name only, and hides the classic taskbar tooltip over an open panel.
- The installer now asks for Windows 10 version 1809 or later, the oldest the app is built for.
Thanks to @mihha for both ideas.
Install
Download TaskbarGroupsFluent-Setup.exe below and run it. If you already have it, the app offers the update when it opens. TaskbarGroupsFluent-Setup-Offline.exe carries the .NET 10 Desktop Runtime inside, for PCs without internet.