I want to offer some criticism of Firefox’s recent emphasis on the sidebar and vertical-tab workflow.
I understand the use case for vertical tabs. If someone regularly keeps dozens or hundreds of tabs open, a vertical list makes those tabs easier to identify and navigate. There is nothing wrong with providing that as an option.
My objection is to designing the browser around that behavior and increasingly treating it as the normal workflow.
The traditional horizontal tab bar is remarkably efficient. It places temporary browser state in a narrow strip above the webpage, preserves the horizontal dimensions of the content area, works naturally with widescreen displays and video, and handles ordinary numbers of tabs perfectly well. On my desktop, I can have roughly twenty tabs open before the layout even begins to become particularly constrained.
By contrast, a persistent sidebar consumes horizontal viewport space—the dimension that is often most valuable for video, responsive websites, and pages that already place secondary content along the sides.
More importantly, I think Firefox should consider what behavior its interface encourages.
An open browser tab is temporary session state. Session Restore is useful, but it is a recovery feature, not a durable information-management system. Information that genuinely matters should be bookmarked, saved, written down, stored in a file, or otherwise placed somewhere intentionally persistent.
Designing the primary browser interface around maintaining enormous tab collections encourages people to use a live browser session as a hybrid bookmark manager, task list, memory aid, and storage mechanism. Firefox is effectively making a poorly bounded information-management habit easier instead of encouraging users to distinguish between an active workspace and information that should actually be preserved.
Good interface defaults teach good procedures.
The browser should function first as a clean workspace. If users want to externalize large amounts of working state into dozens of persistent tabs, Firefox should absolutely support that workflow—but it should be an alternate workflow rather than the architecture around which the default interface is increasingly designed.
There was nothing fundamentally wrong with horizontal tabs. They are familiar, spatially efficient, preserve webpage width, and work extremely well for users who treat tabs as temporary working documents rather than permanent storage.
Please keep horizontal tabs and the minimal top-oriented browsing interface as a first-class experience, and be cautious about making sidebar-oriented workflows increasingly prominent or default simply because they accommodate very large tab collections.
Adding another workflow is an improvement. Reorganizing an already efficient interface around a specialized workflow is not necessarily progress.
Regards,
Taylor H. Fenton
