Bug 141192 [Viewers] Javadoc change about multiple equal elements in StructuredViewer and AbstractTreeViewer
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
}
			fireDoubleClick(new DoubleClickEvent(this, selection));
		}
	}
	/**
     * Handles a tree collapse event from the SWT widget.
     * 
     * @param event
     *           the SWT tree event
     */
    protected void handleTreeCollapse(TreeEvent event) {
        if (event.item.getData() != null) {
            fireTreeCollapsed(new TreeExpansionEvent(this, event.item.getData()));
        }
    }
    /**
     * Handles a tree expand event from the SWT widget.
     * 
     * @param event
     *           the SWT tree event
     */
    protected void handleTreeExpand(TreeEvent event) {
    	if (!(getContentProvider() instanceof ILazyTreeContentProvider)) {
			createChildren(event.item);
		}
        if (event.item.getData() != null) {
            fireTreeExpanded(new TreeExpansionEvent(this, event.item.getData()));
        }
    }