Handle display of missing map types in Topicmap selector
When plugins with custom map types like geomaps or tableviews go missing / are removed from the DMX instance the entries of the according maps stay in the Topicmap selector. Selecting them leads to the infinite spinner. We should find a better way to handle this.
Proposal:
- Display a human readable error message saying which plugin is missing to display the requested view. Users would then know they have to become active or contact admins. Ideally, the message should contain a link to the section in the documentation on how to (re)install a plugin.