class_docstr: A graphical tool for exploring the recursive descent parser.  The tool
  displays the parser's tree and the remaining text, and allows the
  user to control the parser's operation.  In particular, the user
  can expand subtrees on the frontier, match tokens on the frontier
  against the text, and backtrack.  A "step" button simply steps
  through the parsing process, performing the operations that
  ``RecursiveDescentParser`` would use.
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code: def _redraw_quick(self):
      # This should be more-or-less sufficient after an animation.
      self._highlight_nodes()
      self._highlight_prodlist()
      self._position_text()
  
imports: from tkinter import Button, Frame, IntVar, Label, Listbox, Menu, Scrollbar, Tk
  from tkinter.font import Font
  from nltk.draw import CFGEditor, TreeSegmentWidget, tree_to_treesegment
  from nltk.draw.util import CanvasFrame, EntryDialog, ShowText, TextWidget
  from nltk.parse import SteppingRecursiveDescentParser
  from nltk.tree import Tree
  from nltk.util import in_idle
label_desc: Use image node_id 12 for calling the RecursiveDescentApp obj's underlying member method code with example usage: obj._redraw_quick() without return types