diff --git a/AlgebraicDataflowArchitectureModel/src/application/editor/Stage.java b/AlgebraicDataflowArchitectureModel/src/application/editor/Stage.java
index 44ac06e..8b549fe 100644
--- a/AlgebraicDataflowArchitectureModel/src/application/editor/Stage.java
+++ b/AlgebraicDataflowArchitectureModel/src/application/editor/Stage.java
@@ -73,6 +73,7 @@
         mxCell rootCell = (mxCell) graph.getDefaultParent();
         if(rootCell == null) return;
         if(rootCell.getChildCount() <= 0) return;
+        if(rootCell.getChildCount() <= layerNo) return;
 
         graph.getModel().setVisible(rootCell.getChildAt(layerNo), isEnable);
         graph.refresh();