I'm not sure how I managed this one... but a couple of functions are just gone in GMS, specifially the bitmask_set_submask / bitmask_get_submask. I type them, but code completion doesn't recognize them, they are color coded as variables when I type them, and I get "uknown function or script" on them at compile time. Some info... I know It's exclusive to a single project. I tested another project, and it's fine. I've tried deleting caches that I'm aware of, but no joy yet. I noticed it after trying to type one of the functions before correcting a line of code that the code editor had flagged red. I've tried a few other functions, and they seem to show up fine, so I'm pretty sure it's exclusive to these functions. I guess that's all at the moment. I don't know if it's a bug or if I somehow confused Game Maker Studio with something I did. Is there maybe a certain cache or temporary folder I should be looking to delete? Thanks for any help!