Can't believe I didn't realise that this exists, for the longest time I have been screen grabbing and then opening up Pixelmator just to get the HTML color of a part of the web page.
Just click on the CSS property that contains the color, then in the page select the pixels you want as the color.
Original Twitter Post
TIL: Pick color with an eye dropper straight from Dev Tools
Saves screen grabbing and then using from pixelmator pic.twitter.com/aUsW1jQE1r
— Paul Kinlan (@Paul_Kinlan) February 18, 2015