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.
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.
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.