When you go to Gmail in Chrome, you will be asked if you want Gmail to open all email links. Click yes, and clicking on email links in any application on your computer will open a fresh Gmail compose window.

You can set Gmail as your default mail client in Firefox and Internet Explorer as well.

Release track:
Rapid

Editions included:
Google Apps, Google Apps for Business, Government and Education

Languages included:
All languages supported by Gmail

For more information:
http://gmailblog.blogspot.com/2012/02/open-email-links-directly-in-gmail.html
http://support.google.com/chrome/bin/answer.py?hl=en&answer=1382847

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