Disable target property when no compatible properties and set default target enums

com.unity.perception/Editor/Randomization/ParameterElement.cs

             targetField.RegisterCallback<ChangeEvent<Object>>(evt =>
             {
                 ClearTarget();
-                var appFreqEnumIndex = m_ApplicationFrequency.enumValueIndex;
+                var appFreqEnumIndex = m_ApplicationFrequency.intValue;
-                m_ApplicationFrequency.enumValueIndex = appFreqEnumIndex;
+                m_ApplicationFrequency.intValue = appFreqEnumIndex;
                 m_SerializedProperty.serializedObject.ApplyModifiedProperties();
                 ToggleTargetContainer();
                 FillPropertySelectMenu();
             m_TargetGameObject.objectReferenceValue = newTarget.gameObject;
             m_Target.FindPropertyRelative("component").objectReferenceValue = newTarget.component;
             m_Target.FindPropertyRelative("propertyName").stringValue = newTarget.propertyName;
-            m_Target.FindPropertyRelative("fieldOrProperty").enumValueIndex = (int)newTarget.fieldOrProperty;
+            m_Target.FindPropertyRelative("fieldOrProperty").intValue = (int)newTarget.fieldOrProperty;
             m_SerializedProperty.serializedObject.ApplyModifiedProperties();
             m_TargetPropertyMenu.text = TargetPropertyDisplayText(parameter.target);
         }
                 return;
 
             m_TargetPropertyMenu.menu.MenuItems().Clear();
-            m_TargetPropertyMenu.text = parameter.target.propertyName == string.Empty
-                ? "Select a property"
-                : TargetPropertyDisplayText(parameter.target);
-
-            foreach (var option in options)
+            if (options.Count == 0)
-                m_TargetPropertyMenu.menu.AppendAction(
-                    TargetPropertyDisplayText(option),
-                    a => { SetTarget(option); });
+                m_TargetPropertyMenu.text = "No compatible properties";
+                m_TargetPropertyMenu.SetEnabled(false);
+            }
+            else
+            {
+                m_TargetPropertyMenu.SetEnabled(true);
+                foreach (var option in options)
+                {
+                    m_TargetPropertyMenu.menu.AppendAction(
+                        TargetPropertyDisplayText(option),
+                        a => { SetTarget(option); });
+                }
+                m_TargetPropertyMenu.text = parameter.target.propertyName == string.Empty
+                    ? "Select a property"
+                    : TargetPropertyDisplayText(parameter.target);
             }
         }
 

com.unity.perception/Runtime/Randomization/Parameters/ParameterTarget.cs

         [SerializeField] internal GameObject gameObject;
         [SerializeField] internal Component component;
         [SerializeField] internal string propertyName = "";
-        [SerializeField] internal FieldOrProperty fieldOrProperty;
-        [SerializeField] internal ParameterApplicationFrequency applicationFrequency;
+        [SerializeField] internal FieldOrProperty fieldOrProperty = FieldOrProperty.Field;
+        [SerializeField] internal ParameterApplicationFrequency applicationFrequency = ParameterApplicationFrequency.OnIterationSetup;
 
         /// <summary>
         /// Assigns a new target