anchor.diff:  If STEPS is negative, go to next pages instead."
     (select-next-page :prompt-buffer prompt-buffer :steps (- steps)))
   
  -(define-command return-selection (&optional (prompt-buffer (current-prompt-buffer))) ; TODO: Replace by an action which returns the selection as is.
  +(define-command return-selection (&optional (prompt-buffer (current-prompt-buffer)))
     "Have the PROMT-BUFFER return the selection, then quit."
     (prompter:return-selection (prompter prompt-buffer))
     (hide-prompt-buffer prompt-buffer))
   
  -(define-command return-input (&optional (prompt-buffer (current-prompt-buffer)))
  +(define-command return-input (&optional (prompt-buffer (current-prompt-buffer))) ; TODO: Remove if we remove `must-match-p'?
     "Have the PROMT-BUFFER return the selection, then quit."
     (prompter:return-input (prompter prompt-buffer))
     (hide-prompt-buffer prompt-buffer))
  
positive.code:        "M-[" 'select-previous-source
         "return" 'return-selection
         "C-return" 'return-input         ; TODO: Bind to shift-return instead?
         "M-return" 'run-action       ; TODO: Also bind to C-return?
         "C-space" 'prompt-buffer-toggle-mark
         "shift-space" 'prompt-buffer-toggle-mark-backwards
         "M-space" 'prompt-buffer-toggle-mark
  
negative.code:   ((prompter:name "List of actions")
     (prompter:initial-suggestions (prompt-buffer-actions))))
  
  (define-command return-selection-over-action (&optional (prompt-buffer (current-prompt-buffer)))
    "Prompt for an action to run over PROMPT-BUFFER selection."
    (let ((action (prompt
                   :prompter (list
                              :prompt "Action to run on selection"
                              :sources (list (make-instance 'action-source))))))
      (when action
        (prompter:return-selection (prompter prompt-buffer) action)
        (hide-prompt-buffer prompt-buffer))))
  
  (define-command cancel-input (&optional (prompt-buffer (current-prompt-buffer)))
  