# You can get the coordinates of the upper-left corner of a widget by 
# using the x and y methods. 
# The coordinates they return are relative to the parent of the widget
+:

    $x = $widget->x;
    $y = $widget->y;

# for a mouse pointer
  my ($x, $y) = $mw->pointerxy;
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For question #2, you need to understand that a Mainwindow or your $top, is initmately connected to the MainLoop statement. When you destroy one, you destroy the eventloop. So you would need to keep your multiple MainLoops, each in their own subroutine or closure, as there can only be 1 MainLoop running at any time( with certain odd exceptions). So it makes me wonder if your basic program design is correct, maybe you could explain better what you are trying to do, and why you need multiple eventloops.

If you have the need for making multiple toplevel windows within your program, you should consider letting them all share the same MainLoop, and instead of $top->destroy, you could use $top->packForget to just remove the calendar from view, allowing the same MainLoop to keep running for your next use. A MainLoop can have multiple toplevel windows called and or destroyed, as long as the $mw associated with the MainLoop is still intact.

It would look something like this: You make 1 mainwindow which controls the MainLoop, then you can add as many toplevel windows as often as you like.

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


my $mw = MainWindow->new;
$mw->title( "MainWindow" );
$mw->geometry('400x400+30+30');

$mw->Button( -text => "Toplevel", -command => \&do_Toplevel )->pack();

$mw->waitVisibility;

my $tl;
&do_Toplevel; #initialize it in withdrawn state

MainLoop;

sub do_Toplevel {
       
         my $topx = 300;
     my $topy = 100;

#         print $mw->geometry,"\n";
         my ($xs,$ys,$signx,$xp,$signy,$yp) = 
     $mw->geometry =~ /(\d+)x(\d+)([+-]+)(\d+)([+-]+)(\d+)/;
#         print "$xs,$ys,$signx,$xp,$signy,$yp\n";
    
         my $xpos = int($xp + $xs/2 - $topx/2);
     my $ypos = int($yp + $ys/2 - $topy/2);
    
        if ( !Exists( $tl ) ) {
         $tl = $mw->Toplevel();
         $tl->geometry($topx.'x'.$topy.'+'.$xpos.'+'.$ypos);
     $tl->title( "Toplevel" );
     #put all your widgets here
         $tl->Button(
        -text    => "Close",
        -command => sub { $tl->grabRelease;
                      $tl->withdraw }
        )->pack;
     $tl->withdraw;
    }
    else {
            $tl->geometry($topx.'x'.$topy.'+'.$xpos.'+'.$ypos);
        $tl->deiconify();
        $tl->raise();
        $tl->grabGlobal;
    }
}
##############################################################
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