Share on Twitter v0.80.2
Simplest add-on for Twitter. Share web pages, links, and selected text on Twitter.com right from the context menu (right click menu) and the toolbar button.
Right click anywhere on a page or link and choose the option "Share on Twitter". Or simply select the text you want to share and right-click. You can also use the toolbar button and option in Tools menu to share the current tab.
Visit homepage for more: https://browsernative.com/twitter-share-firefox/