Multiple duplicate categories when adding launchers

When using MenuLibre to edit my Linux Mint Mate Menu (Whisker Menu) I will get multiple duplicate categories with the same name and won't be able to come back and edit anything in the newly added category.

For instance, I use Variety screen background switcher. The install installs it in the Accessories category in the menu. I wanted to add a launcher in the System Tools category so started the Menu Editor and added it.

Now, I have 2 System Tools entries in the Menu. The regular one and a new one that contains my Variety launcher. The problem is, if I start the Menu Editor again, it doesn't see or allow me to edit that Variety launcher.

Why does it have to add a duplicate category? I don't need a new category. I just want to add a launcher to an already existing category.

I just did a new install and moved a few launchers around and now I have two of each of the following:
Accessories
Office
System Tools
Accessories
Office
System Tools.