AHAH progress type (throbber) and form element with description

When I add a select form item with AHAH like this:
$form['add_type'] = array(
'#type' => 'select',
'#title' => t('Some title'),
'#description' => t('Some description'),
'#default_value' => 0,
'#options' => $options,
'#required' => TRUE,
'#ahah' => array(
'event' => 'change',
'path' => 'some/path-ahah',
'wrapper' => 'type-wrapper',
'method' => 'replace',
'effect' => 'none',
'progress' => array(
'type' => 'throbber',
),
),
);

and change it (call AHAH callback function) I see, that at the right of my select form item appears throbber, but description also goes to the right of that throbber from the next line and all content under select goes up.

How can I solve this problem?