In pen tool and highlighter tool, only three colours can be set at the same time, but is there any way to set four or more colours on the tool bar at the same time? Personally, I use black, red, blue and green frequently, but every time I need to switch one of three colour settings. Since there is still space on the tool bar, the app should allow the users to add more colour settings on the bar (like Microsoft OneNote). What do you think?