title: How to Save custom DockWidgets
body: <p>I want to save my custom DockWidgets (inherited from QDockWidget) with the saveState() / restoreState() function my MainWindow provides.</p>
  
  <p>I have two questions:
  1. How can I save and restore my Dockwidgets?<br>
  - I already tried registering my custom DockWidgets as a QMetaType and implementing the default Constructor, copy Constructor, Destructor and Streaming operators.<br>
  2. How can I identify the loaded DockWidgets?<br>
  - For example: If 2 DockWidgets where saved and I load them with restoreState(), is there a way to get pointers to these loaded Widgets?  </p>
  
  <p>Thanks,
  Tobias</p>