Heyo! To expand a little bit, I have had an idea, I just am not really sure to where to start, so some help would be great.
Idea: So, you know how the Minecraft recipe book has a button? Maybe using the code like that, but instead of opening a little recipe menu, it overlays a second gui, connecting to the same blockstate and accessing a new set of input and result crafting. So, you'd have both, for example, the furnace and the crafting table, and you'd flick between them. Issue is, I have no Idea how buttons are supposed to work in Minecraft, and I don't really know how to find the source code for the crafting table, so that locks me at a dead end right at the beginning. Unless this is some Java skill issue on my part, I'm mainly a C++ dev. Anything, even a, "you're just stupid", would be great, as it would point me in the direction of more general Java googling instead of just Forge