Hey, I mentioned this a while ago and had a little poc that in the end used qt as the gui with two distinct canvas: one for fpl, one for my library. It worked fine as events could impact each other.

With the changes to rendercanvas I got interesting in the idea again and started to tinker. In my dream scenario, I would want to use FPL as the gui where a subplot could act as a rendertarget/context for any other app. With shared device and loop, handing down size and all events etc.

canvas = SubplotCanvas(figure[1, 0].get_subplot_context())

It might be far fetched as this is an abstraction, perhaps I should just render to a texture give those to fpl.
I am not familiar enough with pygfx to really understand what is going on inside FPL yet - but I got the opportunity to use it more, so will be hacking around.