I changed chkbox->IsChecked() to chkbox->GetValue() now, which bypasses
that assertion check.
The question still is, why is the m_style flag corrupted? I stripped
down the dialog code and the xrc down, and the problem persisted. So
this is not a fix, but a workaround. The problem might arise in other
locations again.
Jean-Michel, I didn't get the mailcap message, please check the new
frmOption.cpp on your system.
Regards,
Andreas