Double buffering problems (xdbe) using glMakeCurrent

[John]

Hi

I'm trying to double buffer an animated image being written to an X 
Window using xdbe and glDrawPixels

I'm getting a GLXBadDrawable error when I try to make the xdbe back 
buffer current using glxMakeCurrent. The error occurs in the 
glxMakeCurrentCall in both Cygwin and Linux (RHEL5.0)

Using the back buffer in XDrawString (for example) works fine and using 
the primary Window/Front buffer in glxMakeCurrent also works fine.

The actual back buffer drawable value is contiguous with the Window 
value and works with normal X calls so is clearly correct.

Can't find any reference to this on the web. Any ideas?

Thanks

John