Tcl/Tk script library providing enhanced functionality for Tk or Ttk
entries, BWidget Entries, Mentry widgets, Tk or Ttk spinboxes,
Ttk comboboxes, text or ctext widgets, listboxes and tablelist widgets.

* Restrict the set or number of characters that can be entered
  into a widget.
* Manipulate the input characters before inserting into a widget:
  change the color, font, etc.
* Protect parts of a widgets data from being modified or selected.
* Setup callbacks for data modification, insertion cursor movement
  and selection change.
