This extension is for those TB3 users who want the multiple-columns view that TB2 allowed
Quicktext is an extension for Thunderbird that lets you create templates that can be easily inserted into your own emails.
Russian spellchecking dictionary
Ukrainian (uk-UA) spellchecking dictionary
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)