To add to the Desktop Panel, follow these directions:
Click on the protractor icon:
This will bring you to Personal Options>Desktop Nodes:
To add a new Node to the list, click Insert to add it to the top and Append to add it below the item you have selected (blue in focus). Use the Label field to name the addition to your Desktop list.
After clicking save, the new Desktop Node will be listed in the Panel and you can add desktops to that new selection. Please remember this is a setting in Personal Options, so this is only for you.