Some of you may have weak or old devices. That being the case, you may, as I do, use Lubuntu or some other LXDE based distro on the those machines. However, you may also have noticed that the LXDE menu is almost impossible to customize in any way. With that in mind, the following are instructions for removing lxpanel and having mate-panel run in LXDE instead. It adds about 30MB to the RAM load on the system. But, in my view, this is a very small price to pay for such increased functionality.
Open a terminal and enter the following:
sudo apt-get install mate-panel
Then, on the menu, go to "preferences/default applications for LXSession" and choose the "core applications" tab. You will see a list on the right. Look for the "panel" option and change it from "lxpanel" to "mate-panel".
Then log out and back in.
You will find the lxpanel has now been replaced with mate panel. This will change RAM consumption from around 200MB (with lxpanel) to around 230MB (with mate-panel).
You will also need to install "mozo" to be able to edit the mate menu.
sudo apt-get install mozo
As I said, the main advantage of the above customization is that it gives all of the lightweightness of LXDE with the ease of use and easy customisability of mate menu.
All of the above works on Ubuntu server/mini with the vanilla LXDE desktop. It also works on Lubuntu 16.04 LTS. I have not yet tried it on Lubuntu 17.10. But, I should think it will work on that as well.