Write XFCE desktop menus "on the fly" by configuring launcher icons using the cp command.
Key to this is creating a hidden folder ".menus" in your home folder.
Make it hidden by renaming with a dot as the first character of the filename (so you don't accidently delete it later).
Using the XFCE menu editor, create a menu tailored to a specific category.
It could have all things internet on it, so call it internet_menu.xml and save it in your newly created .menus folder.
Carry on creating menus tailored to specific categories as for the example above.
Remember you can drag and drop items from App Finder to the XFCE menu editor.
You can also right click an item in App Finder to get more information, eg. the command to launch the item.
So you have now created a hidden folder .menus, containing for example :
In your file manager (Thunar) there will an option to show or hide hidden files. Hide them to prevent loss or damage.
To write system_menu.xml to the default XFCE menu use the copy command as shown on the next line.
cp /home/myusername/.menus/system_menu.xml /home/myusername/.config/xfce4/desktop/menu.xml
Any launcher icon (bouncy gdesklets included) can be configured to instantly rewrite your desktop menu.
Select App Finder then Desktop Settings then set XFCE to manage your desktop.
Also if you wish, show desktop menu on mouse right click.
The method described is useful to know about and some people might actually prefer to use it as their main menu controller.
For people who are configuration and tweak obsessed it will give them something to configure and tweak.
The only minus point is that to access a particular item you might need one extra click, to change to a different menu.
However if you are managing your website one day and doing office stuff on another, it will help you to eliminate clutter and focus on current tasks.
I hope this is useful to somebody.