Drawing with wxClientDC

[Alejandro]

Hi,
    I'm drawing a line with a wxClientDC on a wxUpdateUIEvent, but the 
line flickers. This is the code of my wxUpdateUIEvent:

        wxClientDC *pclientdc = new wxClientDC(mywindow);
        pclientdc->DrawLine(0, coord_y, mywindow->GetSize().GetX(), 
coord_y);
        delete pclientdc;
        plist->Refresh();

I tried with a wxBufferedDC, but it doesn't work.

Could someone tell me how to fix it?

Thanks
Alejandro