[jitter] Silly jit.gl.sketch problem

Hi,
I just started my first ever jitter project and I managed to run into trouble pretty quickly. (I think) I need to draw the contents of jit.gl.sketch into a jit.matrix so I can do further jitter processing such as jit.dimmap and jit.glue. In the jit.gl.sketch help file it says: 

The jit.gl.sketch object requires one argument: the name of a drawing context. A named drawing context is a named instance of a jit.window, jit.pwindow, or jit.matrix object that has an instance of the jit.gl.render object associated with it. This value may also be set via the OB3D drawto attribute.

So I loaded up the jit.gl.sketch .help patch and added a jit.matrix and a jit.pwindow both named the same as the jit.gl.sketch argument. I can draw into the supplied jit.window totally fine but nothing shows up in the pwindow or the jit.matrix i created. I also tried changing the names of my pwindow and jit.matrix and using the drawto message sent to jit.gl.sketch and jit.gl.render with no success.

Any idea what I'm doing wrong?