use strict;
use Tk;
my $mw = MainWindow->new();
$mw->Button( -text => 'Hola compaņero!' )->pack;
MainLoop;
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Works for me™. What encoding are you using? Codepoint \x{a4} will display as an n-tilde in a Windows cmd prompt, but in utf8 and Tk, it's a generic currency sign. Codepoint \x{f1} is the 'proper' Tk/utf8 n-tilde, but will display as a plus/minus sign in cmd.