The Command Editor is the main route to creating your own buttons, hotkeys, user-defined commands and other functions in Opus. There are several variants of the command editor dialog used throughout the program, although they all have the same basic design.

  

This screenshot shows two variations of the command editor. The one on the left is the editor for a standard toolbar button - the function being edited is the Viewer Pane command from the default toolbar. The one on the right is the editor for the New Lister hotkey.

Some of the options in the command editor can be overridden by the settings for the toolbar the button is in - the Show image, Large image size and Show label options can all be overridden by the options in the Images & Labels setting on the Toolbars tab in the Customize dialog.

The Advanced button at the bottom lets you switch from simple to advanced mode.

More:

Simple Command Editor
Advanced Command Editor
Using the Hotkey Control