Toolbar customization - Thunderbird

It is very easy to customize the layout of the toolbars in Thunderbird. To add/remove buttons or to change the placement of buttons on a toolbar, right-click on the toolbar, select Customize, and then drag the buttons to where you want them to be. To remove a button, drag it down into the special pane that appears just below the toolbar. To add a button, drag it up from that same special pane and place it on the toolbar. If you want, you can even put buttons up on the menu toolbar.

Note: some Thunderbird extensions (such as the Buttons! extension) provide extra toolbar buttons as part of their functionality. Installing an extension does not automatically put its buttons on the toolbar, however. To add these buttons, you should do as described above for adding buttons to the toolbar.