Look at a single row header option

Currently if you have a fixed toolbar it will always be double height:


There are situations where you want the fixed toolbar but want a more compact layout. This is usually when you don't have many formatting options.

This will possibly need some changes in Gutenberg to support it.

Start by locating the fixed-toolbar implementation and reviewing how Gutenberg handles toolbar height and layout. Reproduce the current double-height toolbar, then determine whether a single-row option can be supported here or requires changes in Gutenberg. Done means a fixed toolbar can use a compact single-row layout when requested without breaking existing formatting options.

Written by the indexing model from the issue text.