A white area shows on admin menu

I do not have a solution but I have pinpointed the problem.

/**
* Implements hook_views_default_views().
*/
function model_views_default_views() {

/* Display: Page */
$handler = $view->new_display('page', 'Page', 'models_admin_page');
$handler->display->display_options['path'] = 'admin/content/models/list';
//////////////////////////////////////////////////////////////////////////////// TODO //
$handler->display->display_options['menu']['type'] = 'tab';
//$handler->display->display_options['menu']['type'] = 'default tab';
//////////////////////////////////////////////////////////////////////////////// TODO //
$handler->display->display_options['menu']['title'] = 'List';
$handler->display->display_options['menu']['weight'] = '-10';
return $views;

}

Change `default tab` to `default`, then you will notice that the white area disappears.

REMARK: Setting the type to `tab` instead off `default tab` will break some functionaly in the menu paths.

===========

I am running the admin_menu module and I have changed:

body.admin-menu {
//margin-top: 20px !important; /* TODO */
margin-top: 0px; /* TODO */
}

in file `/modules/contrib/admin_menu/admin_menu.css`

The error is now gone. Be aware that this is not the real solution, the problem lies elsewhere. On the pages that work, the margin is also 20 so it is strange that this change makes it work.

I am just a newbie with limited knowledge!

@liad Regarding the second issue about margins, see #1604950-14: Admin menu CSS causes horizontal scrollbar for a slightly more comprehensive patch.

@liad And regarding the first issue about the administration menu disappearing, at /admin/config/administration/admin_menu try turning on "Keep menu at top of page". Works for me with the admin_menu-7.x-3.0-rc3 without making changes and breaking some things as you indicated. The workbench module has the same problem.