Here it is a basic one. I want to apply my formatting only to the string "world"

#!/usr/bin/perl
use strict;
use warnings;
use Tk;
use Tk::TableMatrix;
my $ArrayWidget;

my $mw = new MainWindow();

my $FontBold = $mw->Font( -weight => 'bold');


    my ($rows,$cols) = (50, 4);
    foreach my $row  (0..$rows){
        $ArrayWidget->{"$row,0"} = "$row";
    }
    foreach my $col  (0..$cols){
        $ArrayWidget->{"0,$col"} = "$col";
    }
my $table = $mw->Scrolled('TableMatrix',
        -state=>'disabled', 
        -rows => $rows, 
        -cols => $cols,
        -colwidth => 20,
        -height => 6,
        -titlerows => 1, 
        -titlecols => 1,
        -variable => $ArrayWidget,
        -wrap=>1,
        -multiline=>1,
        -scrollbars => 'osoe',
        -relief => 'flat',
        -selecttitles => 0,
        -highlightthickness=>0
)->pack();
$table->tagConfigure ("bold",  -bg => "#689bc0");
$ArrayWidget->{"2,2"} = "Hello world";
#Apply tag bold or different font to the string "world", i.e. not to t
+he entire cell 2.2
MainLoop();
[download]

In the mean time I came to the conclusion that this feature is not supported and that I need to insert in any cell another Widget supporting formatting. The question is if the table becomes to "heavy"/unstable if it grows in size and is frequently changed.