I've created an Application that contains a QMdiArea. I can add QMainWindows as subwindows to it, however I cannot change their z-order, by clicking on such a sub window, or by clicking on the appropriate tab.

It's quite alot of code, but this is the part, responsible for adding & creating a new QMainWindow:
Qt Code: 
  1. // So you know the types...
  2. class DocumentWindow : public QMainWindow {};
  3. class ScriptEditWindow : public DocumentWindow {};
  4. class UiDefinitionWindow : public DocumentWindow {};
  5.  
  6. void MainArea::show(...)
  7. {
  8.        // There is no window for this item: Create one
  9. 	if(boost::shared_dynamic_cast<Script>(item))
  10. 		add(new ScriptEditWindow(boost::shared_static_cast<Script>(item), nullptr));
  11. 	else if(boost::shared_dynamic_cast<UiDefinition>(item))
  12. 		add(new UiEditWindow(boost::shared_static_cast<UiDefinition>(item), nullptr));
  13. }
  14.  
  15. void MainArea::add(DocumentWindow* window)
  16. {
  17. 	window->changeState(m_state);
  18. 	auto subWindow = m_area.addSubWindow(window);
  19. 	subWindow->show();
  20.  
  21. 	verify(connect(window, SIGNAL(closed(DocumentWindow*)), SLOT(onSubWindowClosed(DocumentWindow*))));
  22.  
  23. 	emit windowAdded(window);
  24. }
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Both DocumentWindow subclasses pass the parent, passed to the constructor down to DocumentWindow (which passes it to QMainWindow). Changing the parent to m_area (which is a QMdiArea) doesn't change the behaviour.

To demonstrate, here are 2 screenshots. I tried to activate a certain window by clicking the tab, but only the focus changes, the z-order stays the same (which is always the order I've added the windows to QMdiArea):
subwindow2..png
subwindow1..png

Running the Qt example works fine, so the problem must be a part of my code. However I have no idea what could be causing the observed behaviour.