nanogui: Thread: Problem with offscreen drawing.

I am having a problem with off screen drawing. When I try to use on off
screen PixMap and then copy it to the on screen window I get nothing but
a grey window.
I have a window called on screen and a get a NewPixMap when I initialize
this windows. I do not get a new pixMap after the copy since I didn't
see in anything in the docs where it said that the old one was disposed of.

void updateDisplay(void){
    GrClearWindow(offscreenwid,0);
     GrText(offscreenwid, m_gc, 0, y, stda, -1, GR_TFASCII);
    GrCopyArea(m_onscreenwid, m_gc, 0, 0, 640, 210, offscreenwid,
0,0,MWROP_USE_GC_MODE);
    GrFlush();
}

This works just fine as would be expected

void updateDisplay(void){
    GrClearWindow(onscreenwid,0);
     GrText(onscreenwid, m_gc, 0, y, stda, -1, GR_TFASCII);
    //GrCopyArea(m_onscreenwid, m_gc, 0, 0, 640, 210, offscreenwid,
0,0,MWROP_USE_GC_MODE);
    GrFlush();
}
Any ideas?