User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.9) Gecko/20071025 Firefox/2.0.0.9 Build Identifier: 2.0.0.9 (20071031) Create a Group Select Addon by itself that is not part of Penelope. Reproducible: Always Steps to Reproduce: 1. 2. 3. Hold down the Alt key (option for Mac) and click the left mouse button down on an item in the mailbox it will select all messages that have the same value as the item clicked on, and all of those selected messages will be grouped together. For example, Alt/option-clicking on the name of a sender of a message will select all of the messages in that mailbox sent by that person, and move the messages together. Note that the moving of messages in the mailbox list will break the current sort of the mailbox. The Shift key can be used as a modifier to make the selected messages remain in their original positions in the mailbox list, and thus retain the current sort order.

Is this is some penelope-only code?

(In reply to comment #1) > Is this is some penelope-only code? Yes. You can find it implemented in the Penelope extension, which you can get from here: <http://wiki.mozilla.org/Penelope_Extensions>. If someone wants to move this in to Thunderbird, the code for it can be found here: <http://mxr.mozilla.org/mozilla/source/penelope/base/content/messengerOverlay.js>

Confirming RFE.

(get thee out of General)