Cannot load documentation for some internal entries

Possibly related to SCRIPTDOC-29

If "internal" components are displayed in the right column, then clicking on them does nothing (i.e. it does not load the corresponding javadoc nor does it show an error message).

The CSS shows a `cursor: not-allowed;` style. I guess this makes sense for primitive variables like $sdoc, but not for $services.model.

Not all internal components are affected, for example the $services is clickable and does load the ScriptServiceManager javadoc, so maybe this has not really something to do with the element being "internal".