Bug 238299 [Viewers] Collapse All before expanding class/array suppresses display of all but first child node
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
}
	/**
	 * Adds the given child elements to this viewer as children of the given
	 * parent element. If this viewer does not have a sorter, the elements are
	 * added at the end of the parent's list of children in the order given;
	 * otherwise, the elements are inserted at the appropriate positions.
	 * <p>
	 * This method should be called (by the content provider) when elements have
	 * been added to the model, in order to cause the viewer to accurately
	 * reflect the model. This method only affects the viewer, not the model.
	 * </p>
	 *
	 * @param parentElementOrTreePath
	 *            the parent element
	 * @param childElements
	 *            the child elements to add
	 */
	public void add(Object parentElementOrTreePath, Object[] childElements) {
		Assert.isNotNull(parentElementOrTreePath);
		assertElementsNotNull(childElements);
		if (checkBusy())
			return;
		Widget[] widgets = internalFindItems(parentElementOrTreePath);
		
		if (widgets.length == 0) {
			return;
		}
		for (int i = 0; i < widgets.length; i++) {
			internalAdd(widgets[i], parentElementOrTreePath, childElements);
		}