Extend documentation & misc cleanup

docs/customization/custom-fields.md

@@ -74,7 +74,7 @@ If a default value is specified for a selection field, it must exactly match one
 
 An object or multi-object custom field can be used to refer to a particular NetBox object or objects as the "value" for a custom field. These custom fields must define an `object_type`, which determines the type of object to which custom field instances point.
 
-By default, an object choice field will make all objects of that type available for selection in the drop-down. The list choices can be filtered to only show objects with certain values by providing a `query_params` dict in the Related Object Filter field, as a JSON value. More information about `query_params` can be found [here](./custom-scripts.md#objectvar)
+By default, an object choice field will make all objects of that type available for selection in the drop-down. The list choices can be filtered to show only objects with certain values by providing a `query_params` dict in the Related Object Filter field, as a JSON value. More information about `query_params` can be found [here](./custom-scripts.md#objectvar).
 
 ## Custom Fields in Templates
 

docs/models/extras/customfield.md

@@ -42,6 +42,13 @@ The type of data this field holds. This must be one of the following:
 
 For object and multiple-object fields only. Designates the type of NetBox object being referenced.
 
+### Related Object Filter
+
+For object and multi-object custom fields, a filter may be defined to limit the available objects when populating a field value. This filter maps object attributes to values. For example, `{"status": "active"}` will include only objects with a status of "active."
+
+!!! warning
+    This setting is employed for convenience only, and should not be relied upon to enforce data integrity.
+
 ### Weight
 
 A numeric weight used to override alphabetic ordering of fields by name. Custom fields with a lower weight will be listed before those with a higher weight. (Note that weight applies within the context of a custom field group, if defined.)

netbox/templates/extras/customfield.html

@@ -54,7 +54,11 @@
         </tr>
         <tr>
           <th scope="row">{% trans "Related object filter" %}</th>
-          <td>{{ object.related_object_filter }}</td>
+          {% if object.related_object_filter %}
+            <td><pre>{{ object.related_object_filter|json }}</pre></td>
+          {% else %}
+            <td>{{ ''|placeholder }}</td>
+          {% endif %}
         </tr>
       </table>
     </div>