#!/usr/local/bin/perl -w

package StickyButton;
use Tk;
require Tk::Widget;
require Tk::Button;
use base  qw(Tk::Button);
Construct Tk::Widget 'StickyButton';

sub invoke
{
 my $w = shift;
 my $state = $w->cget('-state');
 $w->configure('-state' => 'disabled');
 $w->update;
 $w->Callback('-command');
 $w->configure('-state' => $state);
}

package main;
use Tk;

my $mw = MainWindow->new;
my $b  = $mw->StickyButton(-text => 'Sticky', -command => \&Slow)->pack;

MainLoop;

sub Slow
{
 local $| = 1;
 print "Invoked...";
 my $var = 0;
 $mw->after(5000,sub { $var = 1 });
 $mw->waitVariable(\$var);
 print " done\n";
}

__END__