Add the option to save preferred, individual colours (now: when typing in a colour code and then changing the colour, you have to type in the code again because there is no possibility to go back to your individual colour)

Make it possible to highlight in a rectangle (straight, squared line) and not round

Expand options of highlighting colours (more shiny and bright like real highlighters, packages like pastel colours)

Add option to make highlighting automatically straight (without having to use the shape button)