7+ Taskbar Tweaker allows you to configure various aspects of the Windows taskbar.

Most of the configuration options it provides can’t be tweaked using the taskbar properties or the registry.

A tool that allows you to:

Reorder items within a tab group.
Group/ungroup/show label/hide label per Application ID.
Close/minimize/etc. multiple windows at once.
Change Application ID of windows (that is, grouping whatever windows you want).

You can open it from the tweaker main window, from the tray menu, or optionally by double/middle clicking within the empty space of the taskbar.