If you can take a screen capture (Ctrl + PrntScrn in Windows) and then paste in to MS Paint or similar software you can usually determine the color code anywhere in the captured screen. This is helpful if you want to match a background color or use a color from a picture for your background color. The following article gives you the general idea for doing this:
tech.deepumohan.com/2011/04/how-to-get-h...code-from-image.html
The only thing I would add is that you do not need to do the conversion that is mentioned in this article. With the color picker tool we use, you can just type in
rgb(#,#,#) in the box above the Choose button using the appropriate numbers in place of the #'s.
The control will take the rgb() notation and do the conversions itself. The advantage of this is that most MS Paint type programs will let you edit colors and they usually will provide the correct RGB numbers.