Defaulting title to empty string

Author: StanleyGoldman

src/UnityExtension/Assets/Editor/GitHub.Unity/UI/TreeControl.cs

@@ -20,7 +20,7 @@ public abstract class Tree<TNode, TData>: TreeBase<TNode, TData>
         [SerializeField] public Rect Margin = new Rect();
         [SerializeField] public Rect Padding = new Rect();
 
-        [SerializeField] public string title;
+        [SerializeField] public string title = string.Empty;
         [SerializeField] public string pathSeparator = "/";
         [SerializeField] public bool displayRootNode = true;
         [SerializeField] public bool isCheckable = false;