QMdiArea changes the subwindow tab activation when lost focus

I have built a QtGui application with a simple QMdiArea. This mdi area is in tabbed view mode with movable tabs. I have created a new action and slot to add new subwindows in the mdi area. Everything is ok, but when the app is run there is a bug with the activation of the tabs.

I have attached all this code to reproduce the issue (main.cpp, QtGuiApplication.h, .ui and .cpp)

To reproduce this bug, please, follow these steps:

• Compile the files
• Run the application
• Create three subwindows with the add window toolbar button
• Move the last subwindow titled "wnd_3" to the second position
  • The current window is "wnd_3"
  • The positions of the subwindows should be: wnd_1, wnd_3 and wnd_2
• Lost the focus of the app going to other application in your desktop
• Come back to the app
  • BUG: when the focus is restored, the current subwindow is changed from the previous "wnd_3" to the "wnd_2" (that is the last in the tab bar)

This issue is independent of the Activation order or any kind of QmdiArea::WindowOrder