Dolphin does not display generic folder icons

Leap 42.1
KDE

Dolphin does not display generic folder icons for icon themes other than “Breeze”

For example, choosing the “Adwaita” icon theme and logging out & in results in folders such as “Documents” and “Music” showing with a customized icon but generic folders show nothing.

This occurs for existing folders and when creating a new folder.

Have experimented with other icon themes as well.

Theme “Breeze” appears to display OK.