If you want open url without remove it, middle-click it, or right click and open link in new tab, or drag it to any position on tabbar you want.
Due to Firefox limitation, If you are looking for a more beautiful icon works with both Dark/Light theme, follow steps below:
That's it, the icon will looks like built ins.
- Type about:config in the addressbar, and press Enter.
- Click the "I accept the risk!" button.
- Type svg in the searchbar on top of the page, and press Enter.
- Find preference name "svg.context-properties.content.enabled", double click it, the status will become "modified" and value become "true".