User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:220.127.116.11) Gecko/20100701 SeaMonkey/2.0.6 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:18.104.22.168) Gecko/20100701 SeaMonkey/2.0.6 In the message list pane, in the threaded view, if you select a line displaying a "+" or "-" and then type Return (Enter), it both expands or collapses the thread AND also opens the message (in a separate window). Reproducible: Always Steps to Reproduce: 1. Set the message list to threaded view. 2. Select a message list line that displays a "+" or an "-" symbol. 3. Type Return (Enter). Actual Results: The message list expands the thread if the line had a "+", or collapses it if it had a "-", and SeaMonkey also opens a new window displaying the message. Expected Results: SeaMonkey should have EITHER expanded/collapsed the thread OR opened the new message window. There should be separate keystrokes for opening a message vs. toggling the thread expansion.
To expand the current thread, (the one selected in the threads pane and currently collapsed), hit the right-arrow key. To collapse the current thread, make sure that its top message is selected then hit the left-arrow key. Hitting the left-arrow key on a message not first in its thread goes to its parent (the message to which that message replies). You may also, of course, click the +/- (or, depending on the theme, the triangle pointing either right or down) to toggle the expanded/collapsed state of a thread; or at the keyboard, \ (backslash) will collapse all threads at once, * (star) will expand them. On SeaMonkey 2.1a3pre on Linux, I see both the current thread expand (but never collapse) and also the current message open when I hit Enter. I believe that this is the intended behaviour. If SeaMonkey 2.0.x does it differently, I don't think the bugfix will be ported.
Having spoken with Neil, this is not ideal behaviour, so confirming for the moment.