diff --git a/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/TwinColumnSelection/TwinColumnSelectionMainPanel.java b/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/TwinColumnSelection/TwinColumnSelectionMainPanel.java
index f73eb46..7f42ac0 100644
--- a/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/TwinColumnSelection/TwinColumnSelectionMainPanel.java
+++ b/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/TwinColumnSelection/TwinColumnSelectionMainPanel.java
@@ -1,19 +1,42 @@
 package org.gcube.portlets.widgets.ckandatapublisherwidget.client.ui.TwinColumnSelection;
 
+import com.github.gwtbootstrap.client.ui.Button;
 import com.google.gwt.core.client.GWT;
 import com.google.gwt.uibinder.client.UiBinder;
+import com.google.gwt.uibinder.client.UiField;
 import com.google.gwt.user.client.ui.Composite;
+import com.google.gwt.user.client.ui.VerticalPanel;
 import com.google.gwt.user.client.ui.Widget;
 
+/**
+ * The twin column panels for selection of the files to attach to the catalague product.
+ * @author Costantino Perciante at ISTI-CNR (costantino.perciante@isti.cnr.it)
+ *
+ */
 public class TwinColumnSelectionMainPanel extends Composite{
+	
+	@UiField 
+	VerticalPanel leftColumn;
+	@UiField 
+	VerticalPanel rightColumn;
+	@UiField
+	Button addToSelected;
+	@UiField
+	Button addToSelectedWithChild;
+	@UiField
+	Button addToUnselected;
+
 
 	private static TwinColumnSelectionMainPanelUiBinder uiBinder = GWT
 			.create(TwinColumnSelectionMainPanelUiBinder.class);
 
 	interface TwinColumnSelectionMainPanelUiBinder extends
-			UiBinder<Widget, TwinColumnSelectionMainPanel> {
+	UiBinder<Widget, TwinColumnSelectionMainPanel> {
 	}
 
+	/**
+	 * Constructor
+	 */
 	public TwinColumnSelectionMainPanel() {
 		initWidget(uiBinder.createAndBindUi(this));
 	}
diff --git a/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/TwinColumnSelection/TwinColumnSelectionMainPanel.ui.xml b/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/TwinColumnSelection/TwinColumnSelectionMainPanel.ui.xml
index 9b2de08..bd31337 100644
--- a/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/TwinColumnSelection/TwinColumnSelectionMainPanel.ui.xml
+++ b/src/main/java/org/gcube/portlets/widgets/ckandatapublisherwidget/client/ui/TwinColumnSelection/TwinColumnSelectionMainPanel.ui.xml
@@ -2,28 +2,27 @@
 <ui:UiBinder xmlns:ui="urn:ui:com.google.gwt.uibinder"
 	xmlns:g="urn:import:com.google.gwt.user.client.ui" xmlns:b="urn:import:com.github.gwtbootstrap.client.ui">
 	<ui:style>
-	.simple-panel-style {
-		border: medium;
-		border-color: black;
-	}
+	<!--
+	EMPTY
+	-->
 	</ui:style>
-	<g:HTMLPanel width="100%">
-		<b:Row>
-			<b:Column size="5" ui:field="leftPanel">
-				<g:VerticalPanel width="100%" height="100%"
-					styleName="{style.simple-panel-style}"></g:VerticalPanel>
-			</b:Column>
-			<b:Column size="2" ui:field="centralPanel">
-				<g:VerticalPanel>
-					<b:Button icon="ANGLE_RIGHT"></b:Button>
-					<b:Button icon="DOUBLE_ANGLE_RIGHT"></b:Button>
-					<b:Button icon="ANGLE_LEFT"></b:Button>
-				</g:VerticalPanel>
-			</b:Column>
-			<b:Column size="7" ui:field="rightPanel">
-				<g:VerticalPanel width="100%" height="100%"
-					styleName="{style.simple-panel-style}"></g:VerticalPanel>
-			</b:Column>
-		</b:Row>
+	<g:HTMLPanel>
+		<b:FluidContainer>
+			<b:FluidRow>
+				<b:Column size="5" ui:field="leftColumn">
+					<g:VerticalPanel ui:field="leftContainer"></g:VerticalPanel>
+				</b:Column>
+				<b:Column size="2" ui:field="centralPanel">
+					<g:VerticalPanel>
+						<b:Button icon="ANGLE_RIGHT" ui:fied="addToSelected"></b:Button>
+						<b:Button icon="DOUBLE_ANGLE_RIGHT" ui:field="addToSelectedWithChild"></b:Button>
+						<b:Button icon="ANGLE_LEFT" ui:fied="addToUnselected"></b:Button>
+					</g:VerticalPanel>
+				</b:Column>
+				<b:Column size="5" ui:field="rightColumn">
+					<g:VerticalPanel ui:field="rightContainer"></g:VerticalPanel>
+				</b:Column>
+			</b:FluidRow>
+		</b:FluidContainer>
 	</g:HTMLPanel>
 </ui:UiBinder> 
\ No newline at end of file