Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hi there monks

The following issue disturbs me: I'm using overrideredirect to remove decorations and as a result the widget is always on top. This is usually fine, but sometimes I want to have a popup on top of the MW, but overrideredirect seems to always win. Is there anyway to make a window on top of an overrideredirect window? I've extended a famous example to emphasize the issue 

#!/usr/bin/perl -w

use strict;
use Tk;

my $mw = tkinit;

my $notification = $mw->Toplevel();
$notification->geometry('+400+400');
$notification->overrideredirect(1);    # Remove window decorations
$notification->withdraw;               # Hide display window

$notification->Label(
    -text       => 'Your message displayed here.',
    -foreground => 'white',
    -background => 'black',
    -height     => 5
)->pack;

$notification->Button(
    -text    => 'Press Me',
    -command => sub {my $msg = $mw->messageBox(-icon => 'error', 
                       -message => "No tests selected", 
                       -title => 'Error', -type => 'Ok', 
                       -default => 'Ok');  
                     }

)->pack;
$mw->Button(
    -text    => 'Display Notification Window',
    -command => \&display_note
)->pack;

MainLoop;

sub display_note {
    $notification->deiconify;
    $notification->raise;
    
    # this is where you setup a condition to withdraw it
    $notification->after( 5000, \&hide_note );
}

sub hide_note {
    $notification->withdraw;
}

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Re: Prevent overidedirect from being always on top (1+1 != 2 )
by Anonymous Monk on Jan 27, 2015 at 09:22 UTC

    So you're saying that your messageBox doesn't show on top of the $notification?

    It does for me, win32, Tk 804.030

[reply]
      Well on KDE (Linux) - it doesn't :(
[reply]
[reply]
Re: Prevent overidedirect from being always on top
by Anonymous Monk on Jan 27, 2015 at 21:22 UTC
    Here is something you might work on; you can turn off the overrideredirect flag. Possibly you could work out a system to remove the flag when you need to place something on top, then restore the flag when done. 
    #!/usr/bin/perl
use warnings;
use strict;
use Tk;

my $mw = tkinit;
$mw->geometry("200x300+200+200");

$mw->overrideredirect(1);   # set the override-redirect flag
$mw->packPropagate(0);      # prevent the window being resized
                           # for this demo
$mw->Button(
   -text       => 'Quit',
   -command    => sub { Tk::exit(0) },
)->pack(
   -side       => 'bottom',
);

# after a delay:
# withdraw
# clear the override-redirect flag
# re-map the window
$mw->after(
   4000,
   sub {
       $mw->withdraw;
       $mw->overrideredirect(0);
       $mw->deiconify;
       $mw->raise;
   }
);
# NB:
# "Mastering Perl/Tk" mentions that clearing
# the override-redirect flag will not cause
# the window manager to supply decorations.
# This is true, but at least on KDE, clearing
# the flag, then unmapping and mapping the
# window puts decorations in place.
#
# Your mileage may vary.

MainLoop;

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[reply]
[d/l]

      That is clever, but is it needed?

      as far as I can tell, it isn't needed, as the messagebox pops up on top of the notification no matter what happens 

      
#!/usr/bin/perl --
use strict; use warnings;

use Tk;

Main( @ARGV );
exit( 0 );

sub Main {
    my $mw = tkinit( );
    $mw->geometry('+300+400');
    
    my $notification = $mw->Toplevel( );
    $notification->geometry('+400+400');
    $notification->overrideredirect(1);    # Remove window decorations
    $notification->withdraw;               # Hide display window
    $notification->Label(
        -text       => 'keep clicking toggle ',
        -foreground => 'white',
        -background => 'black',
        -height     => 5
    )->pack;

    $notification->Button(
        -text    => 'Press Me',
#~         -command => [ \&important_message, $notification ], ## not 
+needed
        -command => \&important_message,
    )->pack;
    
    $mw->Button(
        -text    => 'Display Notification Window',
        -command => [ 'deiconify', $notification ],
    )->pack->focus;
    $mw->Button(
        -text    => 'toggle topmost notification ',
        -command => [ \&toggle_topmost , $notification ],
    )->pack;
    $mw->Button(
        -text    => 'hide notification ',
        -command => [ 'withdraw', $notification ],
    )->pack;
    
##    $mw->WidgetDump; ## debugging aid
    MainLoop;
}

sub important_message {
#~     my( $n ) = @_;
    my( $n ) = $Tk::widget;
#~     my $msg = $mw->messageBox( ## works to raise above $notificatio
+n on win32, might not work on all platforms
    my $msg = $n->messageBox(
        -icon => 'error', 
        -message => "No tests selected", 
        -title => 'Error', -type => 'Ok', 
        -default => 'Ok',
    );
}
sub toggle_topmost {
    my( $n ) = @_;
    warn $n->attributes;
    $n->attributes(-topmost => ! $n->attributes(-topmost ) );;
    $n->parent->raise;
    $n->parent->focus;
}

__END__
__END__

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