  B - Breakpoints buffer.
  C - Command buffer (the debugger shell)
  D - Display buffer (also known as Watch buffer)
+ d - go down frame (with numeric argument goes down that many frames)
  O - Output window
  V - Variables buffer
+ u - go up one frame (with numeric argument goes down that many frames)
+ U - go to source frame
  S - Stack trace buffer
  ? - This help text.
 "))))

	     "Step one line (skip functions).")
    (gud-def gud-print  "p %e"        "\C-p"
	     "Evaluate Ruby expression at point.")
    (gud-def gud-remove "clear %d%f:%l" "\C-d"
	     "Remove breakpoint at current line")
    (gud-def gud-run    "run"       "R"

(defun rdebug-secondary-buffer-populate-map (map &optional menu)
  (define-key map "B" 'rdebug-display-breakpoints-buffer)
  (define-key map "C" 'rdebug-display-cmd-buffer)
  (define-key map "d" 'gud-down)
  (define-key map "D" 'rdebug-display-display-buffer)
  (define-key map "O" 'rdebug-display-output-buffer)
  (define-key map "s" 'gud-source-resync)
  (define-key map "S" 'rdebug-display-stack-buffer)
  (define-key map "u" 'gud-up)
  (define-key map "V" 'rdebug-display-variables-buffer)
  (define-key map "?" 'rdebug-display-secondary-window-help-buffer))

(defun rdebug-display-breakpoints-buffer ()
