diff --git a/src/main/java/org/gcube/portlets/user/td/columnwidget/client/ChangeColumnTypePanel.java b/src/main/java/org/gcube/portlets/user/td/columnwidget/client/ChangeColumnTypePanel.java
index a1d853d..6b16073 100644
--- a/src/main/java/org/gcube/portlets/user/td/columnwidget/client/ChangeColumnTypePanel.java
+++ b/src/main/java/org/gcube/portlets/user/td/columnwidget/client/ChangeColumnTypePanel.java
@@ -910,6 +910,7 @@ public class ChangeColumnTypePanel extends FramedPanel implements
 
 					@Override
 					public void onSuccess(ArrayList<ColumnData> result) {
+						comboColumnReferenceType.reset();
 						storeComboColumnReferenceType.clear();
 						storeComboColumnReferenceType.addAll(result);
 						storeComboColumnReferenceType.commitChanges();