Hello Dear Monks,

I'm trying to create my first GUI and don't understand the following :

use strict;
use warnings;

use Tk;
use Tk::DialogBox;

my $main_window = MainWindow -> new();

$main_window -> bind ( "<Control-Key-c>" , \&add_client ) ; # Ctrl c

MainLoop;

sub add_client {

  my $add_client_win = $main_window -> DialogBox (
    
    -title => 'Ajouter un client' ,
    -buttons => [ 'Valider' , 'Annuler' ]
  );

    # BUG HERE BUG HERE BUG HERE BUG HERE BUG HERE BUG HERE BUG HERE 
    
    #my $firstname_line = $add_client_win -> add ( 'Label' , 

    #    -height => '30'
        
    #) -> pack(
    
    #    -side => 'top' ,
    #    -fill => 'x'
    #);
        
    # END BUG END BUG END BUG END BUG END BUG END BUG END BUG END BUG 
     
    # -- CANTON --
    
    my $canton_line = $add_client_win -> add ( 'Label' , 
    
        -height => '30'
        
    ) -> pack(
    
        -side => 'top' ,
        -fill => 'x'
    );
    
  my $label_canton = $canton_line -> Label (

        -font => 'Helvetica 10 bold' ,
    -text => 'Localisation :',
        -padx => '10' ,
        -pady => '5'
        
    ) -> pack (
    
        -side => 'left' 
    );
    
    my ($canton_data, $canton_display );

    my $canton_choice = $canton_line -> Optionmenu(

        -options => [
            [ 'Genève' =>               '000' ] , 
            [ 'Vaud' =>                 '100' ] , 
            [ ' - Chablais vaudois' =>  '110' ] , 
            [ ' - Lausanne' =>          '120' ] ,
            [ ' - Montreux-Vevey' =>    '130' ] ,
            [ ' - Morges' =>            '140' ] ,
            [ ' - Nyon' =>              '150' ] ,
            [ ' - Yverdon' =>           '160' ] ,
            [ ' - Arc lémanique' =>     '170' ] ,
            [ 'Valais' =>               '200' ] ,
            [ ' - Chablais valaisan' => '210' ] ,
            [ ' - Bas Valais' =>        '220' ] ,
            [ ' - Haut Valais' =>       '230' ] ,
            [ 'Fribourg' =>             '400' ] ,
            [ 'France voisine' =>       '500' ] ,
            [ 'Paris' =>                '600' ] ,
            [ 'Cote d Azur' =>          '700' ] ,
            [ 'Italie' =>               '800' ] ,
            
            ] ,
        -command => sub { } ,
    -variable => \$canton_data ,
    -textvariable => \$canton_display
        
    ) -> pack(
    
        -side => 'right' ,
    );
    
  my $reponse = $add_client_win -> Show ( ) ;    
}
[download]

This code works, but when I uncomment the lines between BUG HERE and END BUG, the -text option in my $label_canton disappears.

If I minimize the window or hide it with another window from another app and restore it the text is here again.

And I don't understand WHY

Thanks.

Have a nice day<>/p

P.S Ctrl-c to see the dialogbox

complete code here