Menu Editor Bugs

 * Mint 19.3, updated at 10th May 2020
 * 64 bit system

**Issue**

1. If using the Cut a Menu Item and Paste it into another Menu, the Cut one reappears in its original Menu, this creates a duplicate.

2. If there are two instances of a Menu Item in two different Menus, either from using Cut or Copy, if then Delete one instance of the Menu Item the other one also removes.

3. If use Delete on a Menu Item, when the Restore System Configuration is used it moves all items back to original places and reticks unticked ones but does not restore Menu Items that were deleted using Delete, ie System Info (app, menu item)

4. Some Menu Items can appear in the Menu called Other when they have been unticked if they were previously put in a new Menu and renamed in Properties, ie Firewall Configuration (app, menu item)

**Steps to reproduce**
Right click Menu, select Config, in Menu settings- Menu, Open the Menu Editor.....

**Expected behaviour**
Cut a Menu Item should remove it from the Menu when its Paste into another Menu. 

If Delete is used on a Menu Item it should not delete all other instances of that Item.

Restore System Configuration should restore any Menu Items removed by Delete.

Start by opening the Menu Editor through the described Menu settings path and reproduce each of the four reported cases on the stated Cinnamon setup. Trace the Menu Editor entry point and its handling of cut, copy, delete, rename, and Restore System Configuration; done means each operation preserves independent instances and restoration returns deleted items and their original state.