Confirmed on Fedora Core 7, OpenSuse 10.2, Windows 2000 and XP.
When running attached script it emits quite a few blankish lines and after that spits out
error writing "stdout": invalid argument
without any apparent reason. And stdout is still writable. In comp.lang.tcl Twylite figured out that [$t get ...] returns not-quite-empty value 0xC3 and considered "some sort of encoding problem" being there.
Drawing widget or changing length of sample text changes snippets behavior, selected category is mostly a guess.
Expected behavior: not giving me errors, naturally .)