Shared OpenGL Rendercontext

Hi,

I'm currently working on a WPF based UI which must be able to use the same render data in multiple control instance.
To be able to support this I had to tweak the OpenGl Control and the CreateRenderContext methods.

Basically I check on control creation if the control is the first one and if not I provide the main render context to enable context sharing.

Although my solution works it isn't perfect, as currently all control instances always share their data. But maybe anyone is interested in what I've done and has ideas how to optimize it.

Even better would be if sharing between rendercontexts could be implemented into SharpGL.

Cheers Thomas