1. Workspace (Zen) - The ability to separate tabs by context (e.g., "Work") within a single window. This eliminates tab clutter without forcing users to open multiple browser windows. Classification: Firefox's current containers are inconvenient and less intuitive than Zen's workspace.
2. Persistent pinned tabs and Folders (Zen) - Full folder support for organizing active tabs in the sidebar, along with "global" pinned tabs/folders that stay accessible across all created workspace.
3. Web panels (Vivaldi) - A feature allowing users to add websites (like messengers notes, translator, music players and e.t.c.) to a narrow sidebar. These panels should open side-by-side with the main content without switching the active tab.
These elements should be arranged in the browser as follows (in these case, vertical tabs on the left):
Workspace, Persistent pinned tabs and Folders are positioned exactly as they are in Zen Browser, while Web panels – to avoid cluttering the vertical tabs – are placed in a separate sidebar on the right. To ensure this sidebar doesn't constantly take up space, it should appear only when hovering over the right edge of the screen (functioning just like vertical tabs do in Zen).
