It once served the purpose to replace the standard Perl/Tk Entry widget in order to reflect the Entry's state.
This is standard behavior of an Entry widget by now, so you can just use a plain Entry widget (at least, in Tk 800.x).
DEPENDENCIES
See Makefile.PL for a list of dependencies.
COPYRIGHT AND LICENCE
Put the correct copyright and licence information here.
Copyright (C) 2016 by Alexander Becker,
Copyright (c) 1997-1998 Achim Bohnet.
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself, either Perl version 5.16.3 or,
at your option, any later version of Perl 5 you may have available.