G'day PilotinControl,

I don't know if there's some confusion between a mouse button and a Button widget; however, what you appear to be asking for is already the default behaviour.

The change in the default colours is only different shades of grey and perhaps not all that obvious. Run the following code to see what's happening more clearly.

#!/usr/bin/env perl

use strict;
use warnings;

use Tk;

my $mw = MainWindow::->new();

my %colours = qw{
    -background red -foreground yellow
    -activebackground yellow -activeforeground red
};

my $button = $mw->Button(-text => 'Test', %colours)->pack();

MainLoop;
[download]

Having done that, if what you're seeing is not what you want, please describe what different behaviour you're looking for.