Did you know that you could add another toolbar to Firefox without needing to install an add-on? This customization feature is often overlooked and can come in handy if you need some extra space to store your buttons or any other toolbar elements you have added to Firefox.
The first thing you will want to do is right-click on your navigation toolbar and select "Customize…". Next, click on the button that reads "Add New Toolbar". You will then want to give your new toolbar a name. Once you have done that – you will see a new toolbar space added to your Firefox toolbar layout. Simply drag the icons over that you want to add to this new toolbar and hit the button labeled, "Done".
Here is the new toolbar I created with the Cut, Copy and Paste buttons added to it:
To hide your custom toolbar from within Firefox, just right-click on the navigation toolbar, and uncheck the custom toolbar you created. If you no longer want your toolbar then go in to customize your Firefox navigation layout again and drag all of the buttons you have added to that toolbar off. This toolbar should then disappear.
Hope that helps you get a little more out of this feature of Firefox that you do not hear that much about!