Workspace won't add or delete mod elements

As the title says, my Workspace won't add in any new mod elements into the game, nor will it delete any mod elements from the game.

Here is a picture of my current Workspace  [ https://prnt.sc/1uhaaci ]

As you can see, there is an item called "CarbonizedG..." (Carbonized Gunpowder), and a block called "Testblocke".

Neither of these mod elements appear in-game. Here is a picture of my current mod Tab. [ https://prnt.sc/1uhac8j ]

As you can see, i'm hovering over a textureless item which is a "Tttttttttttttttttttt spawn egg", which was a test mob which I deleted the mod element of.

However, the mod element still is in-game, even though it has been deleted from my Workspace.

Does anyone know how I can fix this? I can currently not delete or add any mod elements to my mod, which is problematic.

I'm on Windows 10 64-bit, MCreator version 2021.2.36710. [ https://prnt.sc/1uhb210 ]