"Qt 5.6.2 (x86_64-little_endian-llp64 shared (dynamic) debug build; by MSVC 2015)" 
 (created) hwnd= 0x2a004ee
QWinWidget() winId= 0xb60054
WM_ACTIVATEAPP wParam (active)= 1 lParam(thread)= 7088
WM_ACTIVATE wParam: high(minState)= 0 low(active)= 1 lParam(HWND)= 0x0
WM_SETFOCUS 0x0
WM_LBUTTONUP
QWinWidget(dialogW)= 0x146050e Ancestors of 0x146050e GWL_HWNDPARENT= 0x2a004ee GA_PARENT= 0x2a004ee GA_ROOT= 0x2a004ee GA_ROOTOWNER= 0x2a004ee
>QMessageBox::exec()
WM_KILLFOCUS 0x0
WM_ACTIVATE wParam: high(minState)= 0 low(active)= 0 lParam(HWND)= 0x170050a
MyMessageBox::setVisible true internalWinId= 0x170050a Ancestors of 0x170050a GWL_HWNDPARENT= 0x146050e GA_PARENT= 0x10010 GA_ROOT= 0x170050a GA_ROOTOWNER= 0x2a004ee
WM_ACTIVATE wParam: high(minState)= 0 low(active)= 1 lParam(HWND)= 0x170050a
WM_SETFOCUS 0x170050a
MyMessageBox::setVisible false
<QMessageBox::exec() 0
WM_ACTIVATE wParam: high(minState)= 0 low(active)= 0 lParam(HWND)= 0x0
WM_ACTIVATEAPP wParam (active)= 0 lParam(thread)= 7088
WM_KILLFOCUS 0x0
WM_DESTROY
External WM_DESTROY received for  QWidgetWindow(0x228076d1850, name="QWinWidgetClassWindow") , parent:  QWindow(0x0) , transient parent:  QWindow(0x0)