diff --git a/Assets/Scripts/Drag&Drop/DraggablePlaceholder.cs b/Assets/Scripts/Drag&Drop/DraggablePlaceholder.cs
index 3655553..45c32bf 100644
--- a/Assets/Scripts/Drag&Drop/DraggablePlaceholder.cs
+++ b/Assets/Scripts/Drag&Drop/DraggablePlaceholder.cs
@@ -14,6 +14,9 @@ public abstract class DraggablePlaceholder : MonoBehaviour
     protected Rect _lvlBoundsCache;
     protected bool _isOnValidPosition;
     
+    /// <summary>
+    /// calculate level boundaries and finds main camera.
+    /// </summary>
     protected virtual void Start()
     {
         _mainCamCache = Camera.main;