The first small box on the left will save the colour when you click on the colour bar and you can click on that box again to make an identical colour selection later. The second box shows the colour that your cursor is currently hovering over.
As with the drop down list (which you can still use) simply highlight the text you want to colour and then use either the drop-down list or the colour bar to choose your colour.
Note: Depending on the browser that you are using this modification may not be available to a small percentage of users, but you will still be able to use the drop down selector.