diff --git a/src/Bonsai.Gui.ZedGraph/BoundedGraphPanel.cs b/src/Bonsai.Gui.ZedGraph/BoundedGraphPanel.cs
index b1dcd8b..f252df5 100644
--- a/src/Bonsai.Gui.ZedGraph/BoundedGraphPanel.cs
+++ b/src/Bonsai.Gui.ZedGraph/BoundedGraphPanel.cs
@@ -41,6 +41,10 @@ public int Capacity
 
         protected override void OnInvalidated(InvalidateEventArgs e)
         {
+            if (GraphPane is null)
+            {
+                return;
+            }
             double? maxValue = null;
             var curveList = GraphPane.CurveList;
             for (int i = 0; i < curveList.Count; i++)