fix: property decorators produces visual artefacts

Assets/OneLine/Editor/Drawers/SimpleFieldDrawer.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Reflection;
 using System.Collections;
 using System.Collections.Generic;
 using UnityEditor;
@@ -9,9 +10,26 @@ internal class SimpleFieldDrawer : Drawer {
 
         public override void Draw(Rect rect, SerializedProperty property) {
             EditorGUI.BeginProperty(rect, GUIContent.none, property);
-            EditorGUI.PropertyField(rect, property, GUIContent.none);
+            DrawProperty(rect, property);
             EditorGUI.EndProperty();
         }
 
+        /*
+         * WORKAROUND
+         * Unity3d `feature`: EditorGUI.PropertyField draws field 
+         * with all decorators (like Header, Space, etc) and this behaviour 
+         * can not be ommited.
+         * see: http://answers.unity3d.com/questions/1394991/how-to-preserve-drawing-decoratordrawer-like-heade.html
+         * Headers and Separators (provided by one-line) produces artefacts.
+         * We solve this problem with reflection, but we call internal method
+         * and this may be dangerous: unity3d developers may change API =(
+         */
+        private void DrawProperty(Rect rect, SerializedProperty property){
+            //EditorGUI.PropertyField(rect, property, GUIContent.none);
+            typeof(EditorGUI)
+                .GetMethod("DefaultPropertyField", BindingFlags.NonPublic | BindingFlags.Static)
+                .Invoke(null, new object[]{rect, property, GUIContent.none});
+        }
+
     }
 }

README.md

@@ -357,37 +357,3 @@ public class Example : ScriptableObject {
 **Result:**
 
 ![Fixed Length Attribute Example](mdsrc/separator-attribute-example.png)
-
-# Known issues
-
-## Property decorators on nested fields
-
-If nested field marked with some property decorator attribute (like `Space` or `Header`), decorator continues drawing and produces visual artefacts. I do not know how to prevent this behaviour. And community doesn't know too: [see my question without answers](http://answers.unity3d.com/questions/1394991/how-to-preserve-drawing-decoratordrawer-like-heade.html)
-
-**Example:**
-
-```csharp
-using System;
-using UnityEngine;
-using OneLine;
-
-[CreateAssetMenu]
-public class Example : ScriptableObject {
-    [SerializeField, OneLine]
-    private ThreeFields threeFields;
-
-    [Serializable]
-    public class ThreeFields {
-        [SerializeField]
-        private string first;
-        [SerializeField, Header("Header is here")]
-        private string second;
-        [SerializeField]
-        private string third;
-    }
-}
-```
-
-**Result:**
-
-![One Line Attribute Example](mdsrc/issue-decorators-example.png)