Part of the RPG I'm making is minigames on the protagonist's laptop, this meant I had to make a mini desktop interface within the game. It has its own immediate mode UI and button interface, (not using ImGui for this), and window draw functions can take a callback to functions that run their "apps" so the rendering is injected in the pipeline and scissored and placed correctly. All of this is using SimplyRend.
I was working on the shell application and implemented string and vector types to have an easy to use tokenizer, here is the thing in action.