This container has no own layouting logic; you have to tell where the widget shall be placed. The size of the widgets is determined automatically, but you can override that by requesting a certain size via set_size_request() .

While it's very simple to place and layout the widgets, they are fixed: Resizing the window doesn't move or resize the widgets. Use it only when it's absolute necessary; dynamic containers are often the better choice.

<?php
$w = new GtkWindow();
$w->set_title('GtkFixed test');
$w->connect_simple('destroy', array('gtk', 'main_quit'));

$btn = new GtkButton('Button');
$txt = new GtkEntry();

$fixed = new GtkFixed();
$w->add($fixed);

$fixed->put($btn, 10, 100);
$fixed->put($txt, 50, 10);
$btn->set_size_request(150, -1);

$w->show_all();
Gtk::main();
?>