My guess is that if you do:

while(  $text =~ /($pattern)/g ) {
        my $startindex = $-[0];
        my $endindex = $+[0];    
        my $capture = $1;
        my $vsoChars = $VShape->Characters;

        $vsoChars->{Begin} = "$startindex";
        $vsoChars->{End} = "$endindex";
        $vsoChars->{Text} = $capture;
        $vsoChars->SetProperty( 'CharProps', 1, $color );
}
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or even:

while( $text =~ /($pattern)/g ) {
        my $vsoChars = $VShape->Characters;

        $vsoChars->{Begin} = "$-[0]";
        $vsoChars->{End} = "$+[0]";
        $vsoChars->{Text} = $1;
        $vsoChars->SetProperty( 'CharProps', 1, $color );
}
[download]

they will also work.