Hi, it may help to know that the calling widget is the first argument $_[0] pass to any Tk callback. This code may show you what is happening. Notice how the Entry widget changes with each Tab.
#!/usr/bin/perl
use strict;
use warnings;
use Tk;
my $mw = MainWindow->new();
my $entry1 = $mw->Entry()->pack();
my $entry2 = $mw->Entry()->pack();
my $entry3 = $mw->Entry()->pack();
my %after = ($entry1 => $entry2,
$entry2 => $entry1,
);
$mw -> bind('all','<Tab>',sub{
print "@_\n";
($after{$_[0]} // $_[0])->focus;
}
);
$mw->MainLoop();
exit(0);