protected void onInsert(int index, Widget child) {
super.onInsert(index, child);
assert child instanceof ContentPanel : "AccordionLayoutContainer must be ContentPanels";
ContentPanel cp = (ContentPanel) child;
cp.addBeforeExpandHandler(handler);
cp.addExpandHandler(handler);
cp.setCollapsible(true);
cp.setHideCollapseTool(hideCollapseTool);
cp.setAnimCollapse(false);
cp.setTitleCollapse(titleCollapse);