code: public void removeResourceFromProject(String resourcename) throws CmsException {
  
          // TODO: this should be also possible if the resource has been deleted
          CmsResource resource = readResource(resourcename, CmsResourceFilter.ALL);
          getResourceType(resource).removeResourceFromProject(this, m_securityManager, resource);
      }
docs: Removes a resource from the current project of the user.<p>
  
  This is used to reduce the current users project with the
  specified resource, in case that the resource is already part of the project.
  The resource is not really removed like in a regular copy operation,
  it is in fact only "disabled" in the current users project.<p>
  
  @param resourcename the name of the resource to remove to the current project (full current site relative path)
  
  @throws CmsException if something goes wrong