Your code worked well enough for me to see the direction that you are going. Some suggestions:

• With the pack geometry manager, make frames to put your widgets into. I think here, one frame for the menu buttons and one frame for the display that varies according to the File menu option selected. I highly suspect that some of the spacing problems would be solved by using frames instead of putting all of the widgets into the MainWindow. You can pack and unpack a frame. Try that to make things "disappear" within a window.
• I re-coded "Show_ResetPassword_menu" to show how to have that communicate with other subs. Note the -textvariable. Note the binding of <Return>.
• The user interface could be easier. See if you can make one screen with all of the concepts of: add user/update user password/delete user. Normally this sort of screen would stay there until some other menu option is selected, perhaps a menu button for Reports or whatever.One advantage of a GUI is that it can present multiple options at once.

Hope this helps.

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

 
my $mainwindow = MainWindow->new();
$mainwindow->geometry("600x150");
$mainwindow->title("Add/Delete/Reset Password");

# Disable the window Resize
# $mainwindow->resizable(0,0); # Why??? don't need it?
 
my $main_menu = $mainwindow->Menu();

$mainwindow->configure(-menu => $main_menu);

# File
my $menu_menu = $main_menu->cascade(-label=>"Menu", -underline => 0, -
+tearoff=>0);
   $menu_menu->command(-label=>"Password Reset for users", -underline=
+>0, -command=>\&Show_ResetPassword_menu);
   $menu_menu->command(-label=>"Add User", -underline=>0, -command=>\&
+Show_AddUser_menu);
   $menu_menu->command(-label=>"Delete User", -underline=>0, -command=
+>\&Show_DeleteUser_menu);
   
# About
$main_menu->command(-label=>"About", 
                    -command=>sub{$mainwindow->messageBox(-title=> "Ab
+out", -message=>"Version 3.0.0", -type => "ok")});
                    
MainLoop();

my $user;

sub password_reset
{
    my $answer = $mainwindow -> messageBox(
           -message=>"Password Reset for user: $user",
           -title=> "Password",
           -type=>"YesNoCancel",
           -icon=>"info");
           
    if ($answer =~ /yes/i)
    {
       # code to reset password goes here....
       
       # whatever log messasges you want
       print "PASSWORD RESET SUCEEDED: $user\n"; # a log entry?
    }
    else
    {
       print "PASSWORD RESET ABORTED: $user\n"; # a log entry?   
    }
}                

sub Show_ResetPassword_menu 
{

    my $label_resetp = $mainwindow->Label(-text=>"Password Reset for u
+ser ", -width => 40) -> pack ( -side=>'left');
    my $entry_resetp = $mainwindow->Entry(-width => 30, -textvariable 
+=>\$user )->pack(-side => 'left');
    $entry_resetp->bind("<Return>", \&password_reset);
    my $button = $mainwindow->Button(-text=>"Click to reset", -command
+ => \&password_reset , -width => 15) -> pack ( -side=>'bottom' );
}

# more code modifications to be done by poster....

sub add_user
{
    my $answer = $mainwindow -> messageBox(
               -message=>"Add user: $user",
               -title=> "Password",
               -type=>"ok",
           -icon=>"info");    

}

sub Show_AddUser_menu
{
    my $label_adduser = $mainwindow->Label(-text=>"Add user ", -width 
+=> 40) -> pack ( -side=>'left');
    my $entry_adduser = $mainwindow->Entry(-width => 30)->pack(-side =
+> 'left');
   # $entry_adduser->bind("<Return>", \$adduser_handle_return);
    my $button = $mainwindow->Button(-text=>"Click to reset", -command
+ => \&adduser, -width => 15) -> pack ( -side=>'bottom' );

}

sub Show_DeleteUser_menu {
my $deleteuser_handle_return;

my $label_deleteuser = $mainwindow->Label(-text=>"Delete User ", -widt
+h => 40) -> pack ( -side=>'left');
my $entry_deleteuser = $mainwindow->Entry(-width => 30)->pack(-side =>
+ 'left');
   $entry_deleteuser ->bind("<Return>", \$deleteuser_handle_return);
my $button = $mainwindow->Button(-text=>"Click to reset", -command => 
+\$deleteuser_handle_return, -width => 15) -> pack ( -side=>'bottom' )
+;

        $deleteuser_handle_return = sub {
        $mainwindow -> messageBox(
                -message=>"Delete User",
                -title=> "DELETE",
                -type=>"ok",
                -icon=>"info");    
                                    }

}
[download]

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.