If you want to manually do the deleting in the label, you can do it with something like:

$label->configure(-text=>'');
$label->configure(-text=> $newtext);
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Or if you need to avoid the size of the label from shifting around or flickering, you could do something like:

my $length = length $oldtext;
my $text = ' ' x $length;
$label->configure(-text=> $text);
$label->configure(-text=> $newtext);
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