I like this tool, it's very convenient and easy to use :
You want to highlight something on your screen before taking a screenshot ? Draw an arrow or circle it with the pen. Simple - no need to open a drawing application or anything !
So, to draw something : use meta + shift + mouse.
To revert, I have ctrl+alt+z (maybe I customised it though)
To delete everything drawn : meta+shift+f11
Now you can toy with it and enhance and highlight anything on your screen, and screenshot it !!!
To change "clear all mouuse mark" or "clear last move mark" shortcut
1 open system setting
(menu (the bottom left mint logo in the menu bar)) > application > settings)
2 shortcuts and gestures
3 global shortcut
4 in the "Kde component" drop-down list, select Kwin (you may have to scroll down)
5 change "clear all mouuse mark" or "clear last move mark"
(I hope this answer will help somebody on the web one day, I took some time to create an acount on this forum especially to answer this question ... so just for you !!)