If the current position is on a terminal placeholder when the  EXPAND
  key   is   pressed,  the  Editor  displays  a  description  of  valid
  replacements for the terminal placeholder.

  Pressing the up and down arrows (bound to the GOTO CHARACTER/VERTICAL
  command) allows you to move within the text.

  Pressing the space bar removes  the  text  and  returns  you  to  the
  original buffer without making any changes.

  Pressing any other key clears the text  and  performs  the  operation
  normally associated with the key.