ROText: not read-only, missing bindings

[chrstphrchvz]

ROText in Tcl::pTk is erroneously not read-only (https://rt.cpan.org/Ticket/Display.html?id=125420) and is missing bindings which are documented for Perl/Tk's ROText (https://rt.cpan.org/Ticket/Display.html?id=129754).

I have considered replacing the ROText implementation with one resembling that in Tcl::Tk (i.e. using snit from tcllib). But I find myself unable to concentrate or stay motivated long enough to attempt this successfully.