Add section headers in the sidebar and group contacts in sections
Use cases
Currently all contacts are listed in the sidebar without any grouping. It would help with finding contacts by scrolling to have them visually grouped by last name or first name depending on the current sorting setting.
Desired behavior
Add section headers in the sidebar list and group the contacts in sections. If contacts are sorted by last name, then group contacts by the last name's first letter. If contacts are sorted by first name, then group contacts by the first name's first letter. Only add section headers if contacts with this letter exist.
Benefits of the solution
The sections help with finding a contact by scrolling more quickly.