To merge a section to its preceding section:

  1. Click on the blue o dot symbol shown for it in the editor (see below for an example), or right-click the section in the manuscript outline.

  2. Choose Merge into … (for instance in the below example, Merge into 'Abstract'

This operation is also possible to undo, either with the Undo action, or if you have made edits after that make direct undo possible, by clicking the paragraph and choosing Convert to Section

Example section to be merged

The gutter menu