There are two types of "default" toolbars in Opus.
Which toolbars a Lister opens with by default is determined by where the Lister came from. If the Lister came from a saved layout, its toolbars may have been stored with it. If not, a Lister will usually open with the Default Toolbar Set. This is a special toolbar set that determine's a Lister's initial set of toolbars. Use the Settings / Toolbars / Set As Default Toolbar Set command to update your default toolbar set if you want to change which toolbars are used by default.
The default toolbars in Opus 11 are designed to expose as much as possible of the functionality of the program without appearing too busy or overly complicated. The four toolbars are as follows:
The Menu toolbar:
This toolbar contains the "traditional" drop-down menus, as well as controls for modifying the appearance of the Lister.
The Operations toolbar:
This toolbar contains commands relating to file and folder operations.
The File Display toolbar appears at the top of each file display (unless disabled in Preferences):
This toolbar mainly contains commands related to navigation.
The Images toolbar appears whenever a file display is set to Thumbnails mode:
This toolbar contains basic image manipulation functions.