Field type "page" does not work anymore

[Timo-Breumelhof]

The field type "page" causes an error:

{"message":"Unable to find field class for type: page","reason":"FIELD_INSTANTIATION_ERROR"} alpaca.min.js:5:7172...}

Classic Builder, OC 05.01.01

schema:

{
    "type": "object",
    "properties": {
        "ModuleTitle": {
            "title": "Top Title",
            "type": "string"
        },       
        "ParentPage": {
            "title": "Parent Page",
            "type": "string"
        },
        "ShowTitle": {
            "title": "Show Title?",
            "type": "boolean"
        },
        "Icon": {
            "title": "FontAwsome Icon Code",
            "type": "string"
        }
    }
}

Options:

{
    "fields": {
        "ModuleTitle": {
            "type":"text",
            "helper": "Overrules Showing the current Page Name"
        },      
        "ParentPage": {
            "type":"page",
            "helper": "The Parent Page of the Menu"
        },
        "Icon": {
      "type": "icon",
      "glyphicons" : false,
      "fontawesome" : true
        }
    }
}