Log an error if cannot find a tree element when searching for property parent

Author: arimger

Assets/Editor Toolbox/Editor/Utilities/PropertyUtility.cs

@@ -120,8 +120,13 @@ public static object GetTreePathReference(string treeField, object treeParent)
             }
 
             var fieldType = treeParent.GetType();
-            var fieldInfo = fieldType.GetField(treeField,
-                BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public);
+            var fieldInfo = fieldType.GetField(treeField, BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public);
+            if (fieldInfo == null)
+            {
+                ToolboxEditorLog.LogError($"Cannot find field: '{treeField}'.");
+                return null;
+            }
+
             return fieldInfo.GetValue(treeParent);
         }