The bug is hard to explain so I will add images to show my problem. As you can see in the provided picture the interface is completely empty. Does anyone know how to fix this? I have reinstalled eclipse and the addon multiple times and tried plenty of online tutorials but to no success.
Also, the code that was used is the base JPanel code that is generated when selecting it from the "New -> Other -> JPanel"
Well here is a way to fix this:
In case your get any kind of errors use the marketplace to update your WindowBuilder and that should fix it.