Emu
Link to Emu
Ever wanted to be able to use common UI elements such as text input, checkboxes, radio buttons, dialog boxes or even tab groups in GameMaker? Look no further!
Over the last year and a half I've been working on a GUI system for GameMaker, and now that 2.3 is out I decided to jump on the opportunity to clean up the code and make it properly object-oriented. It's primarily aimed at people looking to make software applications other than games - see the screenshots - but you can use it for whatever you want.
Look inside the demo project or see the online Github wiki for documentation.