Problem With GUI Code Blocks (2023.2)

The "is currently open GUI of ___ of type _____" code block does not include vanilla GUI, and it only includes modded GUI. This is very annoying, because I need to check if the inventory is open, so that if an item is right clicked on another item, the items will "combine" (both be removed and replaced with another item).

If there is another way to do this (which there probably is), I would like to know, mainly because it would probably be a large hassle to fix a problem like this.