The "Make Panel Toggle" operator does not check if active item is an input socket, leading to a situation where it can be called on Boolean output sockets. Doing this creates weird behavior where the panel and associated operators believe it has a toggle, but is not reflected in the UI drawing. Other weird behaviors include being able to rearrange output sockets and apply the operator again to another output socket. This patch adds a check in the operator's poll function to prevent it from being called on output sockets. Pull Request: https://projects.blender.org/blender/blender/pulls/137526