sub openFile {
    my $cb_value;
    my @types =
      ( [ "3d Files", '.3d' ], [ "Excel Files", '.xls' ],
        [ "All files", '*' ] );
    $filename = $mw->getOpenFile(
        -filetypes  => \@types,
        -initialdir => $filename,
        # -initialfile      => $filename,
        -defaultextension => '.3d',
        -title            => 'file to read'
    );

    $mw->Unbusy;
    return 'Cancel' unless ($filename);
    $mw->update;
    $w = $ins->Text(
        -height              => '1',
        -font                => 'Arial 10',
        -wrap                => 'word',
        -relief              => "flat",
        -highlightbackground => 'white',
        -highlightthickness  => '1',
        -highlightcolor      => 'red'
    );
    $w->insert( 'end', "$filename" );
    $ins->windowCreate( 'end', -window => $w );

    my $ww = $ins->Checkbutton(
        -variable => \$cb_value,
        -command  => [
            sub {
                print "$cb_value | ";
                print 'Index = ',
                  $_[0]->index( '@' . $_[0]->pointerx . ',' . $_[0]->pointery ),
                  " | ", $_[0]->get(
                    $_[0]
                      ->index( '@' . $_[0]->pointerx . ',' . $_[0]->pointery )
                      . ' linestart',
                    $_[0]
                      ->index( '@' . $_[0]->pointerx . ',' . $_[0]->pointery )
                      . ' lineend'
                  ),
                  "\n";
            },
            $w
        ]
    );
    $ins->windowCreate( 'end', -window => $ww );
}