O contexto é tudo.
You can customize the Add-on Bar the same way you customize any of the other Firefox toolbars:
- Right-click on an empty section of the Tab Strip, select Customize... and the Customize Toolbar window will open.
Drag and drop the items you want into the Add-on Bar.
2.1. To add an item, drag it from the Customize Toolbar window onto the Add-on Bar where you want it to appear.
2.2. To remove an item from the Add-on bar, just drag it to the Customize Toolbar window.
2.3. To rearrange items, drag them into the order you want them to appear.
When you are finished making changes, click Done to close the Customize Toolbar window and save your selections.
These same steps can be used for customizing other toolbars. See How do I customize the toolbars? for details.