In Papers 3, it was unnecessary to bring up the 'annotate' menu to highlight text. One could highlight and select a color with a single click. It was also possible to delete highlight with a single right-click.
In the current version, you can highlight by right-clicking but you need to click a second time to change color. If you are in the annotate menu, you cannot delete a highlight. You have to get out of it first and then right-click to delete.
My suggestion is to allow all highlighting functionalities with a single right-click (the way it used to be). Fine to keep the annotation functionality in place, but allow for deleting highlights while using them.