Tabs could make better use of the space available

When used on a desktop, there is generally much more space for tabs than is even used.
The drop-down is often unnecessary.
Even on a small phone screen there is usually space when used in landscape mode.

The issue names no file, test, or entry point. Start by locating the tab and dropdown UI, then compare it at desktop and landscape phone widths. Done means tabs use available horizontal space where possible and the dropdown is not shown unnecessarily.

Written by the indexing model from the issue text.