How to force regions to render in Overlay

Question

I've created a Seven-subtheme for use with the Admin Overlay and have added Header and Footer regions, however these do not render, despite showing on the "Demonstrate Regions" page.

I have tried to set overlay_set_regions_to_render(array(...)) in custommodule_init() however this fails to influence anything.

Answer 1

I eventually found the code that does this in overlay.module and applied this to a custom module, using the hook:

function mymodule_system_info_alter(&$info, $file, $type) {
  if ($type == 'theme') {
    $info['overlay_regions'][] = 'header';
    $info['overlay_regions'][] = 'footer';                                                                                                                                                                                                                                            
  }
}

However getting this to take effect required visiting the modules page, I don't believe simply clearing the cache worked.