How to hide core fields in Content types? Drupal-6

I created a content type and added some fields. I can manage how to show them in Diplays Field. But there are some 'core fields' which I can not hide in Displays Fields. 

I need to hide the 'menu system field'. Can I do this? How? 
It would be great to hide it just for an specific role.

I uploaded a picture to show what I mean.
There are two ways you can do this.

You can do this with permissions for some items. 'Menu settings' is controlled by 'administer menu' permission.

If some item is being put onto the page which can't be controlled by permissions then you can use a form alter hook to remove them. I tend to set #access to false rather than completely removing the item from the form. 

There is a big explanation of examples of how to alter forms here