https://bugs.winehq.org/show_bug.cgi?id=55860
--- Comment #2 from Christian PANEL ch.panel@free.fr --- It's an example of MDI application made with OWLNext Framework (I have another example but heavier and with the same framework).
You can find the source here : https://sourceforge.net/p/owlnext/code/HEAD/tree/branches/644/examples/tutor... (step 11 is MDI app example)
I have uploaded the example in both 32 and 64 bit at http://c.panel.free.fr/data/test.tar.gz : just open the app in full screen (MAXIMIZED), open a child window and right click to open a modal dialog box then switch to another application and back (I did it with the mouse at the bootom bar) : the main window returns to a normal window (minimized)
Both versions have the same behaviour (except in windows OS)