XTP11.2 skin problem for regular dll

Hi

I have a problem with skinning in a regular dll static link to mfc.

My program is like this:

app.exe dynamic loading ex.dll, then ex.dll static loading stat.dll.

app.exe using sample code "SkinControls"
ex.dll is a mfc extension dll
stat.dll is a regular dll static link to mfc

The Pseudo-code is like this:

// in app.exe
void OnBtn()
{
Load(ex.dll);
FuncEx();
}

// in ex.dll
void CallFuncEx()
{
StaticFun();
}

// in stat.dll
void StaticFun()
{
CMyDlg dlg;
dlg.DoModal();
}

After opening a dialog the window frame is drawn un-skinned with the dark text and then disappears completely after a few seconds (see screenshots).

BTW, I have try
     FinalizeHookManagement();
     InitializeHookManagement();
It work. I just want to know why? can any one explain this problem, very thank you





Best regards