I’ve added more events to the ITabsStudioEngine interface:
TabExtensionCreated, TabExtensionDestroyed and TabExtensionRenamed events with TabExtensionEventArgs argument containing TabExtension, Tab and Tabs properties.
TabCreated, TabDestroyed and TabRenamed events with TabEventArgs argument containing Tab and Tabs properties.
TabsCreated and TabsDestroyed events with TabsEventArgs argument containing Tabs property.
Argument types are corresponding TabsStudioExt classes, not plain WPF controls as before.
Tabs Studio Blog (organizing Visual Studio document tabs) 