I have fieldsets inside the vertical tabs for a form I'm building, but not great themeing capability, as the #attributes property of the fieldset is ignored.

In the following Image I have CSS attached to first and last, as they are available classes, but what happens when I have multiple tabs appearing (just added General)?
 

$form['images'] = array(

'#type' => 'fieldset',

'#title' => t('Images'),

'#collapsible' => TRUE,

'#collapsed' => TRUE,

'#group' => 'torch_admin',

'#weight' => -10,

 

);

$form['images']['#attributes']['class'][] = 'torch-images';

And I tried the regular syntax for #attributes array also.

Comments

I'll solve this with :nth-child, but would still like to know if there's a way to make the vertical tabs have classes using the Form API.