I accidentally mixed pack and grid in one Tk program, and the program just hung, and even the main window didn't show. Following is a simplified version to show this:

use warnings;
use strict;

use Tk;

my $mw = new MainWindow();
$mw->Button()->grid($mw->Button());
$mw->Button()->pack();
MainLoop;
[download]

However that is not always the case, for example the following version, although it does not neccessarily do what one wants, it at least does not hang:

use warnings;
use strict;

use Tk;

my $mw = new MainWindow();
$mw->Button()->grid();
$mw->Button()->pack();
MainLoop;
[download]

Just curious, does anybody know a way, to force Tk at least show an error or warning in similar situations, to ease the debug? Thanks.