SeaMonkey 2.9 Beta 1
* New locales: Ukrainian (uk) (bug 726486), Chinese (Traditional) (zh-TW).
* The File and Move Bookmarks dialogs are resizable now.
* Lightning toolbars can be customized now.
* HTML5 videos that do not start automatically show a large play button now.
* The Download Manager window supports lightweight themes (Personas) now.
* Ctrl+Shift+K as shortcut for the Lightning Task Quick Filter is supported now.
* Unsorted Bookmarks has been added to the Bookmarks menu and the Personal Toolbar has been renamed to to Bookmarks Toolbar.
* Sounds are now played using libcanberra instead of esound on Linux.
* Sync can sync installed add-ons now (provided they are available from AMO).
* Bookmark This Link has been added to feeds' Website header link context menus.
* "Open in Browser" was added to the context menu for opening a website from RSS.
* Attachments on compose windows can be renamed using F2 on Windows and Linux now.
* Addresses can be dragged from the the address book sidebar now.
* Pasting a URL from the clipboard into the Download Manager window will download it.
* The Feed Subscribe dialog remembers where you place it now.
* A Print button can be added to the compose window toolbar now.
* Spelling settings now have their own preferences pane under Appearance.
* Plugins can be disabled for the whole suite now in addition to Mail & Newsgroups only.
* Support for other message storage formats (pluggable mail stores) has been added.
To enable the new Maildir format (instead of the default Mbox) for new accounts, set mail.serverDefaultStoreContractID to "@mozilla.org/msgstore/maildirstore;1". There is no UI for any of this yet.
* The chrome directory was missing in fresh profiles.
* An IPv6 address literal was not usable as a MailNews server name.
* "View Background Image" in the context menu for stand-alone video content has been disabled.
* Some RSS feeds were not properly recognized.
* Errors attaching anchor parts when sending mail could lead to issues with fancy signature files.
* The UI could freeze on feed biff/get new messages.
* MIME parts in a multipart/related context that were not referred to or could not be displayed inline were not available as attachments.
* The onchange and input events were not fired for all form elements on restore.
* Background tabs were not set to an inactive state.
* A MIME part with content-disposition: attachment was not displayed as an attachment if it did not have a filename.
* The Print button in the MailNews toolbar was misaligned with the Modern theme.
* LDAP address book results were not sorted when autocompleting was active.
* Marking as Junk with "Delete mail marked as junk" set undeleted deleted mail.
* Auto-save will not happen anymore if a message is currently being sent.