User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2) Gecko/20100115 Firefox/3.6 (.NET CLR 3.5.30729) Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.7) Gecko/20100111 Thunderbird/3.0.1 Previous versions of Tb allowed one to highlight then drag and drop the Subject text onto the search bar. This was a very convenient feature for bringing a particular thread in its entirety into view; especially when View>Threads>Unread is set, i.e., it would quickly bring into view all the posts for that subject, including the already read ones. Reproducible: Always Steps to Reproduce: 1. Display Tb Searchbar UI via Customize 2. On Searchbar, select Subject or From filter 3. Select any threaded message on the thread pane 4. Highlight and drag then drop the message pane subject text onto Searchbar Actual Results: The drag and drop capability it ignored Expected Results: The threadpane would display only those that matched the dropped subject text. The workaround is to copy the subject text and then paste it into the search bar but this involves a couple of more steps and is no where near as convenient.

confirmed. probably as a result of the new message header. not sure if it was a conscious decision to not support drag. (unlike Bug 427517 - Header links and addresses are not draggable - which is not a regression)

This might be a regression of bug 489609, where the xul elements used for subject were changed, from textbox to description (see patch in attachment 407439 [details] [diff] [review]). Regression or not, bug 489609 provides important information which is relevant for fixing this bug, so they should be linked. "See also" seems to be the only way of visibly linking bugs in their header area, short of using depends/blocks.