Canvas incompatibility causes GUIs to disastrously flicker

[NaiNonTH]

As reported the issue on https://github.com/vram-guild/canvas/issues/395, when these two mods were working together, GUIs like Inventories and GUI items flicker like the end of the world.

[tr7zw]

I'll disable the screen part next update anyway(at least by default). Canvas is currently not on my list of mods I plan to actively support(same as optifine), so don't think it will be any prio to fix a bug of a broken feature for an unsupported mod.