Blocks annoying video ads on YouTube, Facebook ads, banners and much more.
Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).
German Dictionary (new Orthography) for spellchecking in Mozilla products
Add symbol in header plane to switch between compact and expanded view. Options to switch between one or two lines compact view, which buttons should be displayed in header pane. For Thunderbird 36 and older use version 2.0.9 (see version history)
The "Swiss army knife" of folders. Turn your favorites into tabs - open folders and subfolders, move mails without scrolling around or searching. powerful + easy.
See new mail at a glance after automatic filtering - supports quickFilters addon!
Check the message contents and addresses before you send the message...
Displays icon for user agent of received mails.
"Clean Subject" cleans the subject from multiple occurrences of subject prefixes such as ("Re: Re-2: Re:") and postfixes that are inserted by other clients. Words like "[SPAM]" can be cleaned as well. These prefixes can be defined in the preferences.