Accidental gradle cancel caused custom tabs to not work anymore

I accidently cancelt a gradle task after deleting a custom creative tab. Now the deleted tab still shows up in the "rearange tabs" window. Game cant build properly, and after trying to mess with the files i modified the "<modname>ModTabs.java", which says that it regenerates on build. It doesnt. I messed with this file a lot, but i either 1. didnt have any tabs in game at all or 2. had the tabs in the old configuration with the tab that should be deleted in a bugged state (not named properly etc.)

HOW CAN I FIX THIS