Permissions for resource types

I found this at: opencms-forum.de

How to disable the structured content item from showing up (or being chosen) in the explorer

You have to modify the file opencms-modules.xml, add your content type (in this case Author), then remove the permissions (changing GROUP.Users permissions to -r-v-w-c.

 <explorertype name="Author" key="fileicon.Author" icon="xmlcontent.gif" reference="xmlcontent">
                   <newresource page="structurecontent" uri="newresource_xmlcontent.jsp?newresourcetype=Author" order="225" autosetnavigation="false" autosettitle="false"/>
                   <accesscontrol>
                   	<accessentry principal="GROUP.Administrators" permissions="-r-v-w-c"/>
                       <accessentry principal="GROUP.Projectmanagers" permissions="-r-v-w-c"/>
                       <accessentry principal="GROUP.Users" permissions="-r-v-w-c"/>                                          
                   </accesscontrol>
                   <editoptions>
                       <defaultproperties enabled="false" shownavigation="false"/>
                       <contextmenu/>
                   </editoptions>
               </explorertype>