Update (19/03/2015): The tool now offers three independent custom colors that you can set, instead of just one.
Also, if you have one or more highlights selected when switching between colors, they will be automatically painted using the selected color.

One of the most annoying things when adding comments to PDF files in Adobe Acrobat or Adobe Reader is having to switch colors of the Highlighter tool. It's a cumbersome process that can really slow you down when you want to quickly review and comment a file.
The problem is there's no option to add an icon for the tool in different colors, it has to be done via the Properties Toolbar. Well, not any more!

Using this new tool I've developed it is now possible to switch between colors with a single click on an icon, making the review process much faster and smoother.

You can select between a set of default colors (I can customize these colors for your specific needs, of course): Yellow, Red, Blue, Green, as well as an option to define a custom color, either in RGB, CMYK or Grayscale.

Here's how it looks like in Acrobat XI Pro:

Here I show how to add the buttons to the toolbar, so the Tools panel can be closed while working:

And here's how it's used in Reader XI:

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