It's still there in the menu. I also have it on the toolbar courtesy of an addon. https://addons.mozilla.org/en-US/thunderbird/addon/extra-format-buttons/ I don't recall seeing any hint of a keyboard shortcut so I'm surprised to learn of the one you describe. If the menu item doesn't indicate a shortcut, you could use the keyconfig addon to specify one for yourself. https://addons.mozilla.org/en-GB/thunderbird/addon/dorando-keyconfig/ http://kb.mozillazine.org/Keyconfig_extension:_Thunderbird

Thank you for the information but I don't know where to put the command.

For the other answer, thank you, But after I download the add-on, I didn't where to find the file.