Added null checks to flowchart window reflection code in case of breaking updates

Added null checks to getting the “docked” property of the flowchart
window in case this property gets changed or removed in the future. The
default offset values should still be acceptable.

Assets/Fungus/Scripts/Editor/FlowchartWindow.cs

@@ -95,16 +95,24 @@ namespace Fungus.EditorUtils
             // The docked value doesn't always report correctly without the delayCall
             EditorApplication.delayCall += () => {
                 var flags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance;
-                var isDockedMethod = typeof(EditorWindow).GetProperty("docked", flags).GetGetMethod(true);
-                if ((bool) isDockedMethod.Invoke(this, null))
-                {
-                    EditorZoomArea.Offset = new Vector2(2.0f, 19.0f);
-                }
-                else
+                var dockedProperty = typeof(EditorWindow).GetProperty("docked", flags);
+
+                if (dockedProperty != null)
                 {
-                    EditorZoomArea.Offset = new Vector2(0.0f, 22.0f);
+                    var isDockedMethod = dockedProperty.GetGetMethod(true);
+                    if (isDockedMethod != null)
+                    {
+                        if ((bool) isDockedMethod.Invoke(this, null))
+                        {
+                            EditorZoomArea.Offset = new Vector2(2.0f, 19.0f);
+                        }
+                        else
+                        {
+                            EditorZoomArea.Offset = new Vector2(0.0f, 22.0f);
+                        }
+                    } 
                 }
-            };
+            };    
         }
 
         public static Flowchart GetFlowchart()