Hello, I am running into a Tk issue with a large number of Tk::Label widgets within a scrolled Tk::Pane. After the widgets occupy some mysterious limit of "space", i.e. screen real estate, the widgets are no longer displayed correctly. Run the test code below and scroll all the way to the right until the last displayed Label. Swap the value of $txt to "fix" and "break" the display issue. The geometry manager used does not seem to make a difference (pack vs grid). 
#!/usr/bin/perl

use strict;
use warnings;
use Tk;
use Tk::Pane;

my $mw = MainWindow->new();
$mw->geometry('500x500');

my $pane = $mw->Scrolled( 'Pane', -scrollbars => 'se' )->pack( -side =
+> 'left', -fill => 'both', -expand => 1 );

foreach my $col ( 1 .. 1000 ) {

  # try swapping the values of $txt below
  # my $txt = $col;      # works
  my $txt = "Col $col";  # doesn't work

  # try swapping the geometry managers (same result)
  $pane->Label( -text => $txt, -relief => 'groove', -height => 20 )->g
+rid( -row => 0, -column => $col );
  # $pane->Label( -text => $txt, -relief => 'groove', -height => 20 )-
+>pack( -side => 'left' );
}

MainLoop;

[download]
As you see, when the width of the columns increases to accommodate the "Col" prefix to the label's text, the overall space occupied by all of the widgets increases and they stop being displayed at some point. When only the column number is displayed in the Label's text, there seems to be enough "room" and everything is rendered correctly. Is there some kind of maximum "scrolled space" beyond which Tk::Pane cannot handle? I am running perl v5.16.3 on RHEL 7.2 (don't ask)

In reply to Tk::Pane widget size limit? by jbuck

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