Besides being able to turn toolbars on and off manually, you can configure Opus to show toolbars (or toolbar sets) automatically based on certain conditions.

In certain view modes

Opus can automatically show a toolbar when the display mode changes. For example, the Images toolbar is configured by default to show whenever a file display is set to Thumbnails mode.

View mode toolbars are configured from the Toolbars / View Mode Toolbars Preferences page.

In certain folders

You can configure Opus to automatically show a toolbar whenever you navigate to a certain folder, or to a folder containing predominantly a certain type of file.

Folder-specific toolbars are configured using the Folder Formats system.