title: How can I insert QDockWidget as tab
body: <p>I have a lot of widgets in my application and I know I can drag them during runtime and place over another widget in order to merge them (both widgets are on same place and there are tabs under them which I can use to switch them).</p>
  
  <p>How can I insert QDockWidget like this programmatically from start?</p>
  
  <p>For example I want to add 2 QDockWidgets to bottom that are tabbed so that they are in same area and I can tab-switch them</p>