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Gmail - Add Right Click Menu
Adds a special right click on menu to Gmail. Default right click menu remains visible
Script updated to work with FF3. Please let me know if you experience problems with the updated code.
Currently, the menu lets the user navigate around the site. He or she can jump to "inbox", "compose new", "sent messages", "contacts", etc. Keyboard shortcuts are placed next to each option on the menu. I think this menu could work as a bridge for users who want to memorize the keyboard shortcuts. (Okay, they're not too difficult to learn, but the right click menu did help me memorize 'em.)
I hope to add more advanced functionality soon, such as separate menus for various pages and the ability to issue commands (e.g., "Delete this message").

The first iteration of this script appeared on lifehacker: Gmail Right Click Menu Speeds Up Navigation.
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Nice. Workin' for me.
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@kwbridge. Thanks for the comment. I finally have a fix in place. The script now works with FF3. Please let me know if you encounter any more problems; I will keep testing as well. Thanks again.
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There is a problem with this script in Firefox 3. The right click menu will be embedded in email messages. You won't see it there when composing a message but when someone replies to you it will be in the body of the message. You can see it when writing the message if you switch to plain text formatting. There is also some mention of this in the comments section of the lifehacker article mentioned above.