Hide Group Header insertion and editing mode - OpenERP7

Hide Group Header insertion and editing mode - OpenERP7

I wonder if there is any way to hide the items that I have in the header
of a form, I would like to see them in query mode only.
I know of the existence of CSS classes that allow openERP own show / hide
elements, as *oe_edit_only*, *oe_save_only*, there is also the
*oe_view_only* classes.
<form string="People" version="7.0">
<header class="oe_view_only">
<button string="Wait" name="button_assists" states="assigned"
type="object"/>
....
</header>
...
</from>

But I can not make it work in my case.
I appreciate any help.