Thank you Master++,

Your solution was precisely right!

Furthermore, I was indeed forgetting "that it is, after all, a validatecommand", which was my downfall.

Your answer also illuminates the reason that the printf was causing a successful outcome, namely that the return of printf, like that of print, is "true if successful".  Hence, a successful printf was the equivalent of returning 1, without doing so intentionally.

Thanks for helping me to get past that obstacle!

s''(q.S:$/9=(T1';s;(..)(..);$..=substr+crypt($1,$2),2,3;eg;print$..$/

In reply to Re^2: Strange behavior in -validatecommand; Win32 Perl/Tk version 804.027 by liverpole
in thread Strange behavior in -validatecommand; Win32 Perl/Tk version 804.027 by liverpole

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