Combine Toolbars in Firefox - Save Space & Customize

Optimizing Firefox Toolbars for Enhanced Space
A clean user interface is highly valued, and minimizing unnecessary elements contributes to a more efficient browsing experience. This article details methods for consolidating Firefox toolbars, maximizing screen real estate – particularly useful for users who frequently work with numerous open tabs.
Hiding the Menu Toolbar Using the Personal Menu Extension
Several approaches exist for concealing the Menu toolbar; however, utilizing the Personal Menu extension is a preferred solution. Installation of this extension enables the hiding of the menus toolbar.
The menu toolbar can be temporarily revealed by pressing the Alt key. Furthermore, the extension introduces new options to the menu, which can be tailored to individual preferences or removed entirely.
The Personal Menu Extension can be downloaded from Mozilla Add-ons.
Combining the Bookmarks and Navigation Toolbars
It’s possible to relocate items from the Bookmarks toolbar to other toolbars, effectively merging functionality. Initiate this process by right-clicking within a toolbar and selecting "Customize..."

Subsequently, click and drag the "Bookmarks Toolbar Items" onto the desired toolbar; in this instance, the Navigation toolbar was chosen.

With the bookmarks integrated, the Bookmarks Toolbar can then be hidden.

Hiding the Status bar through the View menu results in an even more streamlined browser interface.

Further customization is achievable, such as removing the Go button, to reclaim additional screen space.