allow viewport layer axes to be set so they can be shared
diff --git a/org.eclipse.nebula.widgets.nattable.core.example/src/org/eclipse/nebula/widgets/nattable/core/example/impl/MultiViewportExample.xtend b/org.eclipse.nebula.widgets.nattable.core.example/src/org/eclipse/nebula/widgets/nattable/core/example/impl/MultiViewportExample.xtend
index 34df83a..69d9f96 100644
--- a/org.eclipse.nebula.widgets.nattable.core.example/src/org/eclipse/nebula/widgets/nattable/core/example/impl/MultiViewportExample.xtend
+++ b/org.eclipse.nebula.widgets.nattable.core.example/src/org/eclipse/nebula/widgets/nattable/core/example/impl/MultiViewportExample.xtend
@@ -13,20 +13,22 @@
 	
 	override createLayer() {
 		val bodyLayer = new CompositeLayer => [
-			addRow(
-				new ViewportLayer => [
+			val viewportOne = new ViewportLayer => [
 					underlyingLayer = new DummyLayer(
 						new AxisImpl(4, 150),  // Horizontal axis
 						new AxisImpl(10, 100)  // Vertical axis
 					)
 					horizontalAxis.minPixelOrigin = 0
 					horizontalAxis.maxPixelSize = 150
-				],
+				]
+			addRow(
+				viewportOne,
 				new ViewportLayer => [
 					underlyingLayer = new DummyLayer(
 						new AxisImpl(10, 150),  // Horizontal axis
 						new AxisImpl(10, 100)  // Vertical axis
 					)
+					verticalAxis = viewportOne.verticalAxis 
 				]
 			)
 		]
diff --git a/org.eclipse.nebula.widgets.nattable.core/src/org/eclipse/nebula/widgets/nattable/core/layer/impl/viewport/ViewportLayer.xtend b/org.eclipse.nebula.widgets.nattable.core/src/org/eclipse/nebula/widgets/nattable/core/layer/impl/viewport/ViewportLayer.xtend
index 21eac2c..d0311fe 100644
--- a/org.eclipse.nebula.widgets.nattable.core/src/org/eclipse/nebula/widgets/nattable/core/layer/impl/viewport/ViewportLayer.xtend
+++ b/org.eclipse.nebula.widgets.nattable.core/src/org/eclipse/nebula/widgets/nattable/core/layer/impl/viewport/ViewportLayer.xtend
@@ -34,6 +34,9 @@
 		verticalAxis = new ViewportAxis(underlyingLayer.verticalAxis, [| fireEvent(new ScrollEvent) ])
 	}
 	
+	def setHorizontalAxis(ViewportAxis horizontalAxis) { this.horizontalAxis = horizontalAxis }
+	def setVerticalAxis(ViewportAxis verticalAxis) { this.verticalAxis = verticalAxis }
+	
 	def void setVisiblePixelRectangle(PixelRectangle visiblePixelRectangle) {
 		horizontalAxis.visiblePixelSize = visiblePixelRectangle.width
 		verticalAxis.visiblePixelSize = visiblePixelRectangle.height