UPADTE: I've been awarded a Tumbleweed badge for this question (Asked a question with no votes, no answers, no comments, and low views for a week). My gut feeling is this is about optimizing Drupal to speed up page loads, but maybe it's something else?
I have a form divided into five fieldsets. The sets are displayed on my page using vertical tabs, like this:
// Form element: vertical tabs.
$form['vertical_tabs'] = array(
'#type' => 'vertical_tabs',
);
// Form elements: fieldset tree.
$form['Fruits'] = array(
'#title' => t('Type'),
'#type' => 'fieldset',
'#tree' => TRUE,
'#collapsible' => TRUE,
'#group' => 'vertical_tabs',
);
...etc.
When the page loads, initially just the plain form appears. It takes about 2-3 seconds for the vertical tabs 'styles' to be applied to the form. In other words, it takes a significant time to load the finished page. Has anyone else had this problem and figured out how to stop/arrest this behaviour?
I am using Zen theme, if that makes any difference. Thanks.