I asked Claude to write one from scratch. A few minutes later it was done with exactly the features I needed. I started with some existing one, but when it couldn't handle multiple pointers (2 hands in VR/AR each with a pointer) without major mods I end up asking Claude if it could replace it with a custom one.

It first said "that's a ton of work" to which I said, "Really? A basic IMGUI needs a texture with glyphs. The abiltiy to draw textured rectangles with vertex colors. Scissor support for clipping. Some hit testing." and it was like, "yea, you're right", and a few mins later it wrote what I needed.

I'm not saying you shouldn't use this library.