Instead of an add button we inject an invitation to create a component.

The invitation can be positioned explicitel like this

<ul>
  [#list components as compontent]
  	[#render content=component]
  [/#list]  
  <li cms:add></li>
</ul>

auto injection
the following algorithm is used to place it:

• if there is a single root div element, it gets injected inside it (at the bottom)
• if there is no such single root element the invitation is placed above the area end marker