public void dispose() {
super.dispose();
if (null != element && element.hasParentElement()) {
element.removeFromParent();
}
targetElementId = null;
}
/** If the DOM element containing the canvas is not visible, we first scroll it into view */
public void ensureViewVisible() {
super.ensureViewVisible();
DOM.scrollIntoView(DOM.getElementById(targetElementId)); // containerDivId
}