diff --git a/WebApp/src/uk/ac/exeter/QuinCe/web/datasets/SensorOffsets/SensorOffsetsBean.java b/WebApp/src/uk/ac/exeter/QuinCe/web/datasets/SensorOffsets/SensorOffsetsBean.java
index f0f4ecf90..e9b94c66b 100644
--- a/WebApp/src/uk/ac/exeter/QuinCe/web/datasets/SensorOffsets/SensorOffsetsBean.java
+++ b/WebApp/src/uk/ac/exeter/QuinCe/web/datasets/SensorOffsets/SensorOffsetsBean.java
@@ -111,6 +111,7 @@ private void reset() {
     instrument = null;
     dataset = null;
     dirty = false;
+    plotData = null;
   }
 
   public String finish() throws Exception {