How to register plug-ins

Plug-ins are distributed in the form of dll files.
You can register to QTTabBar by dropping the dll file to the plug-in list.
Some dll files include multiple plug-ins in them.

Option	opens option dialog of the plug-in if it has options.
Disable	sets the plug-in deactivated. Command buttons are removed from Command Bar if any.
Enable	sets the plug-in activated. You need to add Command Button to Command Bar by yourself, if it provides any.
Uninstall	unregisters all plug-ins that are provided by the dll file. (The dll file itself remains. You can delete it by yourself.)

How to add Command Buttons provided by plug-ins

Open "Command Buttons" in the option window, then drag an item to Command Bar.

How to assign keyboard shortcuts provided by plug-ins

You can do it in "Keyboard Shortcuts" in the option window.