Problem To Be Solved
The user cannot easily tell what aspects of the display are fixed, and which are available for customization.
Interaction context
Under DLM some portlets may be removable, or mutable in other ways, and others may not. The user attempts to (say) delete a portlet, and finds that some can be removed and some can't but there's no way to distinguish them without attempting removal.
Current Solutions
Portlets which cannot be removed should not display the "remove" icon.