I would start with

See Re^3: resizing problem with Tk appl using PackForget, Tk::Scrolled, (inside Tk::Wm sub Scrolled), inside Tk::Frame sub packscrollbars, Tk::WidgetDump, and start with

#!/usr/bin/perl --
#~
#~  perltidy -olq  -csc -csci=3 -cscl="sub : BEGIN END " -otr -opr -ce
+ -nibc -i=4 -pt=0   "-nsak=*"
#!/usr/bin/perl --
use strict;
use warnings;
use Tk qw/ tkinit /;

Main( @ARGV );
exit( 0 );

sub Main {
    my $mw = TkMain( @_ );
    $mw->WidgetDump;    ## use Tk::WidgetDump;
    $mw->MainLoop;
} ## end sub Main

sub TkMain {
    my $mw = tkinit( -bg => 'green', );
    $mw->minsize( 60, 60 );

    my $top = $mw->Pane( -bg => 'orange', )->pack(
        -side   => 'top',
        -expand => 0,
        -fill   => 'x',
    );
    my $label = $top->Label(
        -text => 'Label',
        -bg   => 'pink',
    )->pack( qw/ -side left / );

    my $cans = $mw->Scrolled( Frame => -bg => 'white', )->pack(
        -fill   => 'both',
        -expand => 1,
    );
    my $can = $cans->Canvas(
        -width  => 300,
        -height => 300,
        -bg     => 'pink',
      )->pack(
        -fill   => 'none',
        -expand => 0,
      );

    $top->Button(
        -text    => 'packscrollbars',
        -command => [ \&unforgetScrollbars, $cans ],
    )->pack( qw/ -side left / );
    $top->Button(
        -text    => 'packForget scrollbars',
        -command => [ \&forgetSrollbars, $cans ],
    )->pack( qw/ -side left / );

#~     $mw->bind( '<Configure>' => [ \&gotResized , $cans ] ) ; ## too
+ much
    $mw->bind( $cans, '<Configure>' => \&gotResized );    ## *ok*
## http://www.tcl.tk/man/tcl8.4/TkCmd/bind.htm

    $cans->Subwidget( 'xscrollbar' )->bind( '<Configure>', \&gotResize
+d )
      ;    ## bingo?    ## $xscrollbar->parent->....

    return $mw;
} ## end sub TkMain

sub gotResized {
    warn "@_";
    my( $cans ) = @_;
} ## end sub gotResized

sub unforgetScrollbars {
    my( $cans ) = @_;
    $cans->Subwidget( 'ysbslice' )->pack;
    $cans->Subwidget( 'corner' )->pack;
    $cans->Subwidget( 'yscrollbar' )->pack;
    $cans->Subwidget( 'xscrollbar' )->pack;
    $cans->packscrollbars;
} ## end sub unforgetScrollbars

sub forgetSrollbars {
    my( $cans ) = @_;
    $cans->Subwidget( 'ysbslice' )->packForget;

#~     $cans->Subwidget( 'corner' )->packForget;
    $cans->Subwidget( 'yscrollbar' )->packForget;
    $cans->Subwidget( 'xscrollbar' )->packForget;
} ## end sub forgetSrollbars
__END__
[download]