My Dell Studio 1749 laptop doesn't have a visual indicator for caps or num lock. My solution ...
- add the program indicator-keylock by entering the following command in a MATE terminal
sudo apt install indicator-keylockenter your password when prompted - no text will be displayed as you type your password
- add this program to your computer's start up by opening:
Click Startup Applications
Click Add and you should then see ...
You may assign any name you wish
Command must be indicator-keylock
The next startup will produce a visual indicator briefly on your screen when either caps or numlock is changed