Hello Monks, I am working on a gui application and currently have it up and running, except for the packing and resizing on the main window and widgets inside it. I have a Mainwindow and a Left and Right Frame -

 
use strict;
use warnings;
use Tk;
use Tk::Table;
use Tk::Pane;
use Tk::DialogBox;
use Tk::BrowseEntry;
use Tk::ProgressBar;
require Tk::LabFrame;


##Global Variables
my $ffdir = "";
my $outfdir = "";
my $mmthd;
my $delim='';
my $cols_maskmthd_tbl;
my $mw; #my $xpm; 
my $cols_tbmasked_lbox;
my $mask_but; my $txt;
my $be;
  
    # Main Window
    $mw = new MainWindow;
    $mw->configure(-title=> "SomeTitle");
    $mw->minsize(1020,590);
    $mw->resizable(1,1);
     
      
    #GUI Building Area
    
    ## Build left side frame
    
     my @leftfrm_options = ( '-relief','ridge','-borderwidth',1);
    # Main outer left frame
    my $pane_left_scr = $mw->Scrolled('Pane')->pack( -side => 'left',-
+fill => 'both', -expand => 1);
    
    #my $frm_left = $pane_left_scr ->Frame(@leftfrm_options)->pack( -s
+ide => 'left',-fill => 'both', -expand => 1, -anchor => 'nw' );
    
    my $frm_left_sec1 = $pane_left_scr ->Frame(@leftfrm_options)->pack
+( -side => 'top',-fill => 'both', -expand => 1, -anchor => 'nw' );
    my $frm_left_sec1_left = $frm_left_sec1 ->Frame(@leftfrm_options)-
+>pack( -side => 'left',-fill => 'both', -expand => 1, -anchor => 'nw'
+ );
    my $frm_left_sec1_right = $frm_left_sec1 ->Frame(@leftfrm_options)
+->pack( -side => 'right',-fill => 'both', -expand => 1, -anchor => 'n
+w' );
    
    my $frm_left_sec2 = $pane_left_scr ->Frame(@leftfrm_options)->pack
+( -side => 'top',-fill => 'both', -expand => 1, -anchor => 'nw' );
    my $frm_left_sec2_left = $frm_left_sec2 ->Frame(@leftfrm_options)-
+>pack( -side => 'left',-fill => 'both', -expand => 1, -anchor => 'nw'
+ );
    my $frm_left_sec2_right = $frm_left_sec2 ->Frame(@leftfrm_options)
+->pack( -side => 'right',-fill => 'both', -expand => 1, -anchor => 'n
+w' );
    
    my $frm_left_sec3 = $pane_left_scr ->Frame(@leftfrm_options)->pack
+( -side => 'top',-fill => 'both', -expand => 1, -anchor => 'nw' );
    my $frm_left_sec3_left = $frm_left_sec3 ->Frame(@leftfrm_options)-
+>pack( -side => 'left',-fill => 'both', -expand => 1, -anchor => 'nw'
+ );
    my $frm_left_sec3_right = $frm_left_sec3 ->Frame(@leftfrm_options)
+->pack( -side => 'right',-fill => 'both', -expand => 1, -anchor => 'n
+w' );
    
    my $frm_left_sec4 = $pane_left_scr ->Frame(@leftfrm_options)->pack
+( -side => 'top',-fill => 'both', -expand => 1, -anchor => 'nw' );
    my $frm_left_sec4_left = $frm_left_sec4 ->Frame(@leftfrm_options)-
+>pack( -side => 'left',-fill => 'both', -expand => 1, -anchor => 'nw'
+ );
    my $frm_left_sec4_right = $frm_left_sec4 ->Frame(@leftfrm_options)
+->pack( -side => 'right',-fill => 'both', -expand => 1, -anchor => 'n
+w' );
    
    my $frm_left_sec5 = $pane_left_scr ->Frame(@leftfrm_options)->pack
+( -side => 'top',-fill => 'both', -expand => 1, -anchor => 'nw' );

    my $frm_left_sec6 = $pane_left_scr ->Frame(@leftfrm_options)->pack
+( -side => 'top',-fill => 'both', -expand => 1, -anchor => 'center' )
+;

    my $frm_left_sec7 = $pane_left_scr ->Frame(@leftfrm_options)->pack
+( -side => 'top',-fill => 'both', -expand => 1, -anchor => 'nw' );
    my $frm_left_sec7_left = $frm_left_sec7 ->Frame(@leftfrm_options)-
+>pack( -side => 'left',-fill => 'both', -expand => 1, -anchor => 'nw'
+ );
    my $frm_left_sec7_center = $frm_left_sec7 ->Frame(@leftfrm_options
+)->pack( -side => 'left',-fill => 'both', -expand => 1, -anchor => 'n
+w' );
    my $frm_left_sec7_right = $frm_left_sec7 ->Frame(@leftfrm_options)
+->pack( -side => 'right',-fill => 'both', -expand => 1, -anchor => 'n
+w' );

    my $frm_left_sec8 = $pane_left_scr ->Frame(@leftfrm_options)->pack
+( -side => 'top',-fill => 'both', -expand => 1, -anchor => 'nw' );
    my $frm_left_sec8_left = $frm_left_sec8 ->Frame(@leftfrm_options)-
+>pack( -side => 'left',-fill => 'both', -expand => 1, -anchor => 'nw'
+ );
    my $frm_left_sec8_right = $frm_left_sec8 ->Frame(@leftfrm_options)
+->pack( -side => 'right',-fill => 'both', -expand => 1, -anchor => 'n
+w' );
    
    ###Choose delimiter
    my $choose_delim_lab = $frm_left_sec1_left -> Label(-text=>"Enter 
+or choose a delimiter:",-width => 22,-anchor => 'nw')
    ->pack( -side => 'left',-anchor => 'nw',-fill => 'none');
    
    # If user selects item from list manually, invoke do_search
    $be = $frm_left_sec1_left->BrowseEntry( -variable => \$delim,
                                  -browsecmd => \&set_delim )
    ->pack( -side => 'right', -expand => 1, -anchor => 'nw',-fill => '
+none' );
   
    
    #Choose ff
    my $choose_ff_but = $frm_left_sec2_left -> Button(-text=>"  Choose
+ Files Folder  ", -bg => 'yellow' )
    ->pack( -side => 'top',-expand => 1, -anchor => 'nw' );
    
    my $choose_ff_lab = $frm_left_sec2_right-> Label(-textvariable=>\$
+ffdir,
                                                     -bg => 'yellow')
    ->pack( -side => 'top',-fill=>'x', -expand => 1, -anchor => 'nw'  
+);

    ##Choose out folder
    my $choose_outf_but = $frm_left_sec3_left -> Button(-text=>"Choose
+ Output Folder", -bg => 'yellow', -command => sub { choose_outf_dir(\
+$outfdir) })
    ->pack( -side => 'top',-expand => 1, -anchor => 'nw' );
    
    my $choose_outf_lab = $frm_left_sec3_right -> Label(-textvariable=
+>\$outfdir,
                                                        -bg => 'yellow
+')
    ->pack( -side => 'top',-fill=>'x',-expand => 1, -anchor => 'nw' );
    
    ##Cols to be masked
    
    my $choose_cm_labfra = $frm_left_sec4_left->LabFrame(
                                                -borderwidth => '2',
                                                -label => "Columns To 
+Mask",
                                                -labelside => "acrosst
+op",
                                                -relief => 'groove')
    ->pack( -side => 'top',-fill => 'x',-expand => 1, -anchor => 'nw' 
+);
    
    $cols_tbmasked_lbox = $choose_cm_labfra->Scrolled("Listbox", -scro
+llbars => "se",
                                                    -selectmode => "mu
+ltiple",
                                                    -width => 30, -hei
+ght=> 10)
    ->pack( -side => 'top',-fill => 'x',-expand => 1, -anchor => 'nw' 
+);
    
    my $up_down_lab = $frm_left_sec5-> Label(-text=>" ".chr(8593).chr(
+8595)." ", -font => 'big')
    ->pack( -side => 'top',-expand => 0, -anchor => 'center' );
    
    #Choose Masking method
    
    my $mask_method_labfra = $frm_left_sec4_right->LabFrame(
                                                -borderwidth => '2',
                                                -label => "Choose Mask
+ing Method",
                                                -labelside => "acrosst
+op",
                                                -relief => 'groove')
     ->pack( -side => 'top',-fill => 'x',-expand => 1, -anchor => 'nw'
+ );
    
    
    my $hash_rdb = $mask_method_labfra -> Radiobutton(-text=>"Hash    
+        ",  
                                                    -value=>"hashed", 
+ -variable=>\$mmthd,
                                                    -command=>sub {col
+s_maskmthd_pairs($mmthd)})
    ->pack( -side => 'top',-expand => 1, -anchor => 'w', -pady => 15 )
+;
    
    my $scramble_rdb = $mask_method_labfra -> Radiobutton(-text=>"Scra
+mble            ",  
                                                        -value=>"scram
+bled",  -variable=>\$mmthd,
                                                        -command=>sub 
+{cols_maskmthd_pairs($mmthd)})
    ->pack( -side => 'top',-expand => 1, -anchor => 'w', -pady => 20 )
+;
    
    my $static_rdb = $mask_method_labfra -> Radiobutton(-text=>"Static
+ Value            ",  
                                                    -value=>"static", 
+ -variable=>\$mmthd,
                                                    -command=>sub {col
+s_maskmthd_pairs($mmthd)})
    ->pack( -side => 'top',-expand => 1, -anchor => 'w', -pady => 14 )
+;
    
    
    # allocate a table to the frame
    $cols_maskmthd_tbl = $frm_left_sec6->Table( -columns => 2,
                                                -rows => 7,
                                                -fixedrows => 1,
                                                -scrollbars => 'e',
                                                -relief => 'raised')
    ->pack( -side => 'top',-fill => 'x',-expand => 1, -anchor => 'cent
+er' );
     
    ## Clear ALL
    my $clrall_but = $frm_left_sec7_left -> Button(-text=>"  Clear All
+  ",-activeforeground => 'red', -command => sub {clear_all()})
    ->pack( -side => 'top',-expand => 1, -anchor => 'center' );
    
    ##Execute mask
    $mask_but = $frm_left_sec7_center-> Button(-text=>"  Mask!  ", -co
+mmand => sub {init_mask()})
    ->pack( -side => 'top',-expand => 1, -anchor => 'center' );
    
    #Exit
    my $exit_but = $frm_left_sec7_right -> Button(-text=>"  Exit  ",-a
+ctiveforeground => 'red', -command => sub {exit_final()})
    ->pack( -side => 'top',-expand => 1, -anchor => 'center' );
    
    #Text Area
    my $pane_right_scr = $mw->Scrolled('Pane' )->pack( -side => 'right
+',-fill => 'both', -expand => 1);
    $txt = $pane_right_scr ->Text()->pack( -side => 'top',-fill => 'bo
+th', -expand => 1 );
    
    MainLoop;
    
   sub exit_final {
    exit 0;
  }
[download]

Thank you for the helpful tips kcott, I have now modified my question to be a working example. I also used Tk::Pane as you suggested. The same issue still exists (maybe cause of -fill => 'both', -expand => 1 , as you suggest), but I dont know how else to have the left and right panes, fill the entire left and right halvres respectively and ALSO expand when the application window is expanded. What am I doing wrong? This is what I'm looking for -

---------------------------------------------------------------
|Choose delimiter:           |                                |
|                            |                                |
|Choose Filese Folder        |                                |
|------------- ------------- |                                |
||           ||            | |                                |
||           ||            | |             Text Area          |
||           ||            | |                                |
||           ||            | |                                |
|------------- ------------- |                                |
|                   	     |                                |
|                   	     |                                |
| Clear       Mask      Exit |                                |
---------------------------------------------------------------

Thank you all!
UPDATE :
I was able to fix the issue with - -sticky => 'nsew'

 my $pane_left_scr = $mw->Scrolled('Pane',-sticky => 'nsew')->pack( -s
+ide => 'left',-fill => 'both', -expand => 1);
[download]