Reparenting a widget into another window does not change TLW affinity for TLW children of that widget (4.8 regression)

See attached sample. Under 4.8.5, this program works correctly, that is, if you click in the window "Child", the button will be moved to "Window 2" and the window "Child" will be correctly "reparented" (you can see this by moving the windows).
But in Qt 5.2.0 beta, the "Child" window remains locked to "Window 1", it is not correctly reparented.
This example application is an extension of the issue fixed in https://bugreports.qt-project.org/browse/QTBUG-30707
which was in fact a partial fix.

Steps to reproduce:

• Compile against Qt4
• Minimize and restore Left Window W1, note child window is minimized and restored
• Click on child, note button jumps to Window 2
• Minimize and restore right Window W2, note child window is minimized and restored along with it

• Compile against Qt5
• Minimize and restore Left Window W1, note child window is minimized and restored
• Click on child, note button jumps to Window 2
• Minimize and restore right Window W2, note child window is NOT minimized and restored along with it as it is still transient child of W1 (Linux,Windows)