relocate view port on resize

Signed-off-by: Florian Thienel <florian@thienel.org>
diff --git a/org.eclipse.vex.core/src/org/eclipse/vex/core/internal/widget/BoxView.java b/org.eclipse.vex.core/src/org/eclipse/vex/core/internal/widget/BoxView.java
index 8c87c3e..7cada9b 100644
--- a/org.eclipse.vex.core/src/org/eclipse/vex/core/internal/widget/BoxView.java
+++ b/org.eclipse.vex.core/src/org/eclipse/vex/core/internal/widget/BoxView.java
@@ -77,6 +77,7 @@
 			@Override
 			public void render(final Graphics graphics) {
 				rootBox.setWidth(width);
+				moveViewPortToCursor(graphics);
 			}
 		};