Some properties in JCR app cannot be edited.

I consider this critical and close to a blocker because a project could get into a state where they are unable to edit a value that they need to edit. Maybe they could resort to a groovy script.

To reproduce:

• Open JCR app
• Change "/server/i18n/authoring/enabled" to "false".
•  Get exception.
• Value is not changed. 

 (Works without error in Configuration app.)

Error:
info.magnolia.ui.datasource.jcr.JcrPropertyWrapper cannot be cast to javax.jcr.Node
RpcInvocationException: Unable to invoke method save in com.vaadin.shared.ui.grid.editor.EditorServerRpc caused by InvocationTargetException caused....
 

A more subtle example:
 

• Change /modules/dam/config/enforceDocumentMimeType to false.
• No error.
• Change it back to true.
• Get exception.

 (Works without error in Configuration app.)

 
Another example. * Switch to "contacts" workspace.

• Edit the value of this node "/vvangogh/email"
• Hit the save button.
• Get exception.

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However when I edit this node in "config" workspace from "en" to "de" I get no error:

"/server/i18n/system/fallbackLanguage"