unless you are outputting to two distinct video cards, you don’t want to use to jit.windows.

if you are, then you should enable @shared 1 on both windows, and capture your scene to a texture using jit.gl.node @capture 1.
you can crossfade the textures using jit.gl.pix @gen xfade.

search the forums for more info on these techniques.

well, you’re going to have to give some more info about what’s not working, and preferably post a patch showing what you’ve done.

you’re going to want to start very simple, two render contexts, each with a single object and a jit.gl.node capturing to texture.

i’m also not entirely sure what you’re trying to achieve, so it’s hard for me to recommend proper strategies.
what do you want to do with each scene’s captured texture? are these supposed to be crossfaded on a third window?