#!/usr/local/bin/perl

use Tk;
# Main Window
my $mw = new MainWindow;
$mw->Frame(-background => 'red')->pack(-ipadx =>50, -side => "left", -
+fill => "y");
#Making a text area
my $txt = $mw -> Scrolled('Text',-width => 150, height => 40, -scrollb
+ars=>'e', -font => "fixed 8 bold" ) -> pack ();
$txt->insert('end', "");
#Declare that there is a menu
my $mbar = $mw -> Menu();
$mw -> configure(-menu => $mbar);
#The Main Buttons
my $file = $mbar -> cascade(-label=>"File", -underline=>0, -tearoff =>
+ 0);
my $tool= $mbar -> cascade(-label =>"Tools", -underline=>0, -tearoff =
+> 0);
my $parser = $mbar -> cascade(-label =>"RL Parser", -underline=>0, -te
+aroff => 0);
my $help = $mbar -> cascade(-label =>"Help", -underline=>0, -tearoff =
+> 0);
## File Menu ##
$file -> command(-label => "Home", -underline=>0,
-command=> \&home );
$file -> command(-label => "Check KPI definitions", -underline=>0,
-command=> \&define );
$file -> checkbutton(-label =>"Check for faults", -underline => 0,
-command => \&faults); 
$file -> separator();
$file -> command(-label =>"Exit", -underline => 1,
-command => sub { exit } );
## Tools Menu ##
$tool -> command(-label => "Network planning", -underline=>0,
-command=> \&nwplan );
$tool -> command(-label => " ", -underline=>0,
-command=> \&optimize );
$tool -> separator();
$tool -> command(-label =>"Network Planning Rules", -underline =>1,
-command => sub { 
    $txt -> delete('1.0', 'end');    
    $txt->insert('end',"some text");});

## Parse Menu ##
$parser -> command(-label => "Parse the RL Dump", -underline=>0,
-command=> \&parse );
## Help Menu ##
$help -> command(-label => "About", -underline=>0,
-command=> \&help );
MainLoop;
    sub help {
my ($opt) = @_;
$mw->messageBox(-message=>"This function is not available yet");
}

sub define { 
    
my $mw = new MainWindow; # Main Window
my $frm_name = $mw -> Frame();
my $lab = $frm_name -> Label(-text=>"Enter KPI:");
my $ent = $frm_name -> Entry();
my $but = $mw -> Button(-text=>"Check", -command =>\&push_button1);
my $textarea = $mw -> Frame(); #Creating Another Frame
my $txt = $textarea -> Text(-width=>130, -height=>30, -font=> "fixed 1
+0 bold");
my $srl_y = $textarea -> Scrollbar(-orient=>'v',-command=>[yview => $t
+xt]);
my $srl_x = $textarea -> Scrollbar(-orient=>'h',-command=>[xview => $t
+xt]);
$txt -> configure(-yscrollcommand=>['set', $srl_y],
-xscrollcommand=>['set',$srl_x]);
$lab -> grid(-row=>1,-column=>1);
$ent -> grid(-row=>1,-column=>2);
$frm_name -> grid(-row=>1,-column=>1,-columnspan=>2);
$but -> grid(-row=>4,-column=>1,-columnspan=>2);
$txt -> grid(-row=>1,-column=>1);
$srl_y -> grid(-row=>1,-column=>2,-sticky=>"ns");
$srl_x -> grid(-row=>2,-column=>1,-sticky=>"ew");
$textarea -> grid(-row=>5,-column=>1,-columnspan=>2);
$txt -> insert('end',"some points"
);
MainLoop;
#This function will be executed when the button is pushed
sub push_button1 {
    my $name = $ent -> get();
    if($name eq "TCH Traffic") 
    {$txt -> delete('1.0', 'end');
        $txt -> insert('end',"some text");
    }
    elsif($name eq "SDCCH Drop") 
    {$txt -> delete('1.0', 'end');
        $txt -> insert('end',"some text");}
elsif($name eq "TCH Assignment") 
    {$txt -> delete('1.0', 'end');
        $txt -> insert('end'," some text");}
elsif($name eq "TCH Blocking") 
    {$txt -> delete('1.0', 'end');
        $txt -> insert('end'," some text");}
elsif($name eq "TCH Drop") 
    {$txt -> delete('1.0', 'end');
        $txt -> insert('end'," some text");}

elsif($name eq "HOSR") 
    {$txt -> delete('1.0', 'end');
        $txt -> insert('end'," some text");}

    elsif($name eq "SDCCH Blocking") 
    {$txt -> delete('1.0', 'end');
        $txt -> insert('end',"some text");}
else {$txt -> delete('1.0', 'end');
        $txt -> insert('end'," Wrong Keyword. Please Try Again");
    }
}
}

sub nwplan {
    use Tk;
#Global Variables
my $gender = "TCH Drop";
 # Main Window
my $mw = new MainWindow;
my $frm_name = $mw -> Frame();
my $lab = $frm_name -> Label(-text=>"Name:");
my $ent = $frm_name -> Entry();
my $frm_a = $mw -> Frame();
my $laba = $frm_a -> Label(-text=>"Name:");
my $enta = $frm_a -> Entry();
my $frm_b = $mw -> Frame();
my $labb = $frm_b -> Label(-text=>"Name:");
my $entb = $frm_b -> Entry();

#Define KPI
my $frm_job = $mw -> Frame();
@set = (61,62, 63, 64 ,65 ,66 ,67 ,68 ,69 ,70 ,71 ,72, 73, 74, 75);
#Gender
my $frm_gender = $mw -> Frame();
my $lbl_gender = $frm_gender -> Label(-text=>"Enter the ARFCN of adjac
+ent cell 1");
my $ent = $frm_gender -> Entry();
my $frm_gendera = $mw -> Frame();
my $lbl_gendera = $frm_gendera -> Label(-text=>"Enter the ARFCN of adj
+acent cell 2");
my $enta = $frm_gendera -> Entry();
my $frm_genderb = $mw -> Frame();
my $lbl_genderb = $frm_genderb -> Label(-text=>"Enter the ARFCN of adj
+acent cell 3");
my $entb = $frm_genderb -> Entry();
my $but = $mw -> Button(-text=>"Check", -command =>\&push_button2);
#Text Area
my $textarea = $mw -> Frame();
my $txt = $textarea -> Text(-width=>130, -height=>30, -font=> "fixed 1
+0 bold");
my $srl_y = $textarea -> Scrollbar(-orient=>'v',-command=>[yview => $t
+xt]);
my $srl_x = $textarea -> Scrollbar(-orient=>'h',-command=>[xview => $t
+xt]);
$txt -> configure(-yscrollcommand=>['set', $srl_y],
-xscrollcommand=>['set',$srl_x]);
#Geometry Management
$lab -> grid(-row=>0,-column=>1);
$ent -> grid(-row=>0,-column=>2);
$lbl_gender -> grid(-row=>0,-column=>1);
$frm_gender -> grid(-row=>2,-column=>1,-columnspan=>2);
$laba -> grid(-row=>1,-column=>1);
$enta -> grid(-row=>1,-column=>2);
$lbl_gendera -> grid(-row=>1,-column=>1);
$frm_gendera -> grid(-row=>3,-column=>1,-columnspan=>2);
$labb -> grid(-row=>3,-column=>1);
$entb -> grid(-row=>3,-column=>2);
$lbl_genderb -> grid(-row=>3,-column=>1);
$frm_genderb -> grid(-row=>4,-column=>1,-columnspan=>2);
$but -> grid(-row=>4,-column=>2,-columnspan=>2);
$txt -> grid(-row=>1,-column=>1);
$srl_y -> grid(-row=>1,-column=>2,-sticky=>"ns");
$srl_x -> grid(-row=>2,-column=>1,-sticky=>"ew");
$textarea -> grid(-row=>5,-column=>1,-columnspan=>2);
$txt -> insert('end'," some text");

MainLoop;
## Functions
#This function will be executed when the button is pushed
sub push_button2 {
 $gender = $ent ->get();
 $gendera = $enta ->get();
 $genderb = $entb ->get();
@list = (61,62,63,64,65,66,67,68,69,70,71,72,73,74,75 );
@final = (undef);
@sum = (undef);

 if($gender >= 61 && $gender <= 75 && $gendera >= 61 && $gendera <= 75
+ && $genderb >= 61 && $genderb <= 75)
 { 
  $d = $gender -$gendera;
    $e = $gendera-$genderb;
    $f = $genderb-$gender;
  if( $d == -1 || $d == 0 || $d == 1 || $e == -1 || $e == 0 || $e == 1
+ || $f== -1 || $f == 0 || $f == 1 )
{
  $txt -> delete('1.0', 'end');
$txt -> insert('end'," Incorrect Entries. Check the values entered


Reason: Neigbor cell mismatch");
 
   }
   else {
foreach $key ( @list )
{
    $a = $gender -$key;
    $b = $gendera-$key;
    $c = $genderb-$key;
    
       if( $a == -1 || $a == 0 || $a == 1 || $b == -1 || $b == 0 || $b
+ == 1 || $c== -1 || $c == 0 || $c == 1 )
   {
    next;
   }
   
   else
   {
     push( @final, $key);
    $txt -> delete('1.0', 'end');

      }
}
$size = @final;

@gender = ($gender,$gendera,$genderb);
$txt -> delete('1.0', 'end');
$txt -> insert('end'," The set of allowed frequencies are \n");
$txt -> insert('end'," \t @final");    
$x = $size;
@i= (undef);

for($i=0; $i<$x; $i++)
{    
        for($j=0; $j<3; $j++)
        {        
            $i[$j] =  $gender[$j] - $final[$i];
                
        if($i[$j]<0)
        {
            $i[$j] = (-1)*$i[$j];}
            else
            {
                $i[$j]=$i[$j];
                }
        
        
        }

$total =0;
foreach $xyz(@i)
{
  $total = $total + $xyz;

}
push(@sum, $total);        

}

shift(@sum);
shift(@sum);
$txt-> insert('end'," 
\n  The distance matrix is given as: \n \t@sum");

$txt-> insert('end'," some text"); 
}
}

else
{
  $txt -> delete('1.0', 'end');
$txt -> insert('end'," Please Check the frequencies entered");
 
   }
}
    
    }
    
sub faults 
{ 
#Global Variables
my $gender = "TCH Drop";
 # Main Window
my $mw = new MainWindow;
#Define KPI
my $frm_job = $mw -> Frame();
#Gender
my $frm_gender = $mw -> Frame();
my $lbl_gender = $frm_gender -> Label(-text=>"KPI Affected ");
my $ent = $frm_gender -> Entry();
my $rdb_m = $frm_gender -> Radiobutton(-text=>"TCH Drop",
-value=>"TCH Drop", -variable=>\$gender);
my $rdb_f = $frm_gender -> Radiobutton(-text=>"TCH Blocking",
-value=>"TCH Blocking",-variable=>\$gender);
my $rdb_j = $frm_gender -> Radiobutton(-text=>"TCH assignment",
-value=>"TCH Assignment",-variable=>\$gender);
my $rdb_k = $frm_gender -> Radiobutton(-text=>"SDCCH Blocking",
-value=>"SDCCH Blocking",-variable=>\$gender);
my $rdb_t = $frm_gender -> Radiobutton(-text=>"SDCCH Drop",
-value=>"SDCCH Drop",-variable=>\$gender);
my $rdb_l = $frm_gender -> Radiobutton(-text=>"HOSR",
-value=>"HOSR",-variable=>\$gender);
my $but = $mw -> Button(-text=>"Check", -command =>\&push_button);
#Text Area
my $textarea = $mw -> Frame();
my $txt = $textarea -> Text(-width=>130, -height=>30, -font=> "fixed 1
+0 bold");
my $srl_y = $textarea -> Scrollbar(-orient=>'v',-command=>[yview => $t
+xt]);
my $srl_x = $textarea -> Scrollbar(-orient=>'h',-command=>[xview => $t
+xt]);
$txt -> configure(-yscrollcommand=>['set', $srl_y],
-xscrollcommand=>['set',$srl_x]);
#Geometry Management
$lbl_gender -> grid(-row=>1,-column=>1);
$rdb_m -> grid(-row=>1,-column=>2);
$rdb_f -> grid(-row=>1,-column=>3);
$rdb_j -> grid(-row=>1,-column=>4);
$rdb_k -> grid(-row=>1,-column=>5);
$rdb_l -> grid(-row=>1,-column=>6);
$rdb_t -> grid(-row=>1,-column=>7);
$frm_gender -> grid(-row=>3,-column=>1,-columnspan=>2);
$but -> grid(-row=>4,-column=>1,-columnspan=>2);
$txt -> grid(-row=>1,-column=>1);
$srl_y -> grid(-row=>1,-column=>2,-sticky=>"ns");
$srl_x -> grid(-row=>2,-column=>1,-sticky=>"ew");
$textarea -> grid(-row=>5,-column=>1,-columnspan=>2);
MainLoop;
## Functions
#This function will be executed when the button is pushed
sub push_button {
 if($gender eq "SDCCH Blocking")
 {$txt -> delete('1.0', 'end');
$txt -> insert('end',"*some text");
}
elsif($gender eq "HOSR")
{
    $txt -> delete('1.0', 'end');
    $txt -> insert('end',"  *some text");
    }
    elsif($gender eq "SDCCH Drop")
{    $txt -> delete('1.0', 'end');
    $txt -> insert('end',"*some text*");
    }
    
    elsif($gender eq "TCH Blocking")
{$txt -> delete('1.0', 'end');
        $txt -> insert('end'," some text");
    }
    
    elsif($gender eq "TCH Drop")
{$txt -> delete('1.0', 'end');
    $txt -> insert('end',"some text");
    }
elsif($gender eq "TCH Assignment")
{$txt -> delete('1.0', 'end');
    $txt -> insert('end',"some text");
    }
}}
}
[download]

You said you were using Tcl/Tk, but it looks like a plain Perl/Tk script to me. In any event, your code problem almost certainly stems from having multiple new MainWindow and multiple MainLoop declarations. In Perl/Tk, as in the Highlander, there can only be 1 :-)

The first MainWindow you declare is fine, but all those following ones should be converted to Toplevel windows, which exist under the the single MainLoop of the first MainWindow declared.

Here is a simple usage of Toplevel

#!/usr/bin/perl

use strict;
use warnings;
use Tk;

my $mw = MainWindow->new;
$mw->Label(-text => 'Main Window')->pack;
$mw->Button(
-text => 'Quit Main',
-command => sub{$mw->destroy},
)->pack;

my $top = $mw->Toplevel;
$top->Label(-text => 'Top level Window')->pack;
$top->Button(
-text => 'Exit Top level',
-command => sub{$top->destroy},
)->pack;
$top->transient($mw);

MainLoop;
[download]

---

I'm not really a human, but I play one on earth.
Old Perl Programmer Haiku ................... flash japh