Comment 8 for bug 1802907

Also, this bit of OnUpdateUI does not look right:

        m_delayedErrorMessage = wxEmptyString;

        if( !m_delayedErrorMessage.IsEmpty() )
        {
            // Do not use DisplayErrorMessage(); it screws up window order on Mac
            DisplayError( nullptr, msg );
        }

I think the if-conditional should be looking at msg? Fix this doesn't fix the crash though.