diff --git a/src/main/java/eu/omp/irap/vespa/epntapclient/gui/requestpanel/paramfield/DataProductTypeField.java b/src/main/java/eu/omp/irap/vespa/epntapclient/gui/requestpanel/paramfield/DataProductTypeField.java
index 7fd4e5c..ef1ce6d 100644
--- a/src/main/java/eu/omp/irap/vespa/epntapclient/gui/requestpanel/paramfield/DataProductTypeField.java
+++ b/src/main/java/eu/omp/irap/vespa/epntapclient/gui/requestpanel/paramfield/DataProductTypeField.java
@@ -52,20 +52,30 @@ public class DataProductTypeField extends ParamField {
 	 */
 	public DataProductTypeField(ViewListener viewListener, String paramName) {
 		super(viewListener, paramName);
-		comboBox = new JComboBox<>(DataProductType.values());
-		comboBox.setSelectedItem(DataProductType.ALL);
-		comboBox.setPreferredSize(
-				new Dimension(ParamField.MIN_FIELD_WIDTH, ParamField.FIELD_HEIGHT));
-
-		comboBox.addActionListener(new ActionListener() {
-
-			@Override
-			public void actionPerformed(ActionEvent e) {
-				update();
-			}
-		});
+		this.add(getComboBox());
+	}
 
-		this.add(comboBox);
+	/**
+	 * @return 
+	 * 
+	 */
+	public JComboBox<DataProductType> getComboBox() {
+		if (comboBox == null) {
+			comboBox = new JComboBox<>(DataProductType.values());
+			comboBox.setSelectedItem(DataProductType.ALL);
+			comboBox.setPreferredSize(
+					new Dimension(ParamField.MIN_FIELD_WIDTH, ParamField.FIELD_HEIGHT));
+
+			comboBox.addActionListener(new ActionListener() {
+
+				@Override
+				public void actionPerformed(ActionEvent e) {
+					update();
+				}
+			});
+		}
+		
+		return comboBox;
 	}
 
 	/**
--
libgit2 0.21.2