It gets complicated with Gtk2, because it uses a basic system style file in ./~gtkrc-2.0 , further complicated by Ubuntu's advanced theme, which probably uses pixmaps, which are hard to override. Google for all the gory gtkrc-2.0 details. It does get complex, and you can spend days trying to figure out the themes.

The gtkrc-2.0 file is hard to override for some widgets. See Setting widget bg color in Gtk2

Here is a general purpose override for the gtkrc style file for the Text box. Notice the color of the cursor needs special handling.

#!/usr/bin/perl
use warnings;
use strict;
use Glib qw/TRUE FALSE/;
use Gtk2 '-init';

Gtk2::Rc->parse_string(<<__);

style "my_text" {
font_name ="sans 24"
text[NORMAL] = "#FFAA00"
base[NORMAL] = "#000000"   
GtkTextView::cursor-color = "red"
}

style "my_cursor"{
fg[NORMAL] = "#FF0000"
}

widget "*Text*" style "my_text"
__

my $window = Gtk2::Window->new('toplevel');
$window->set_title('Z');
$window ->signal_connect( 'destroy' => \&delete_event );
$window->set_border_width(10);
$window->set_size_request(400,400);

my $vbox = Gtk2::VBox->new( FALSE, 6 );
$window->add($vbox);
$vbox->set_border_width(2);

my $hbox= Gtk2::HBox->new( FALSE, 6 );
$vbox->pack_end($hbox,FALSE,FALSE,0);

my $ebutton = Gtk2::Button->new_from_stock('gtk-quit');
$hbox->pack_end( $ebutton, FALSE, FALSE, 0 );
$ebutton->signal_connect( clicked => \&delete_event );

# Create a textbuffer to contain that string 
my $textbuffer = Gtk2::TextBuffer->new();
$textbuffer->set_text('yadda yadda yadda');

# Create a textview using that textbuffer 
my $textview = Gtk2::TextView->new_with_buffer($textbuffer);

# Add the textview to a scrolledwindow 
my $scrolledwindow = Gtk2::ScrolledWindow->new( undef, undef );
$scrolledwindow->add($textview);
$vbox->pack_start($scrolledwindow, 1, 1, 0 );

$window->show_all();

Gtk2->main;

#####################################
sub delete_event {
Gtk2->main_quit;
return FALSE;
}
#######################################
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