Currently a switching between the tabs of tabified dock widgets does not change the focus (i. e. send a focus change event). To work around this, one currently has to muck around in the innards of the QMainWindow, by finding a QTabBar* child, then listening to its currentChanged Signal, then using QTabBar itemData and evaluating the inner pointer to find the dock associated with the currently active tab. See http://www.qtcentre.org/threads/21362-Setting-the-active-tab-with-tabified-docking-windows

In an application with a document paradigm, it is very common to apply actions (toolbar, menu) to the view currently in focus, that is why it is very unexpected that clicking on another tab does not send a focus change event.

Imagine a search function that operates on the currently active document. You change the tab then start searching and it searches in a tabbed dock (the previously focused one) that is not even visible!