Bug 5571 JAR Packager: Reveal first checked project
If the list of projects in the JAR Packager is long it is possible that the shown projects are not checked even though there are checked projects (due to current selection). ==> reveal the first checked project.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/jarpackager/CheckboxTreeAndListGroup.java
* @return only the elements which all filters accept
	 */
	protected Object[] filter(ViewerFilter[] filters, Object[] elements) {
		if (filters != null) {
			ArrayList filtered = new ArrayList(elements.length);
			for (int i = 0; i < elements.length; i++) {
				boolean add = true;
				for (int j = 0; j < filters.length; j++) {
					add = filters[j].select(null, null, elements[i]);
					if (!add)
						break;
				}
				if (add)
					filtered.add(elements[i]);
			}
			return filtered.toArray();
		}
		return elements;
	}
	private Object[] getTreeChildren(Object element) {
		return filter(fTreeViewer.getFilters(), fTreeContentProvider.getChildren(element));
	}
	private Object[] getListElements(Object element) {
		return filter(fListViewer.getFilters(), fListContentProvider.getElements(element));
	}
	public Set getWhiteCheckedTreeItems() {
		return new HashSet(fWhiteCheckedTreeItems);
	}
	private void handleUpdateSelection(Map items) {
		Iterator keyIterator= items.keySet().iterator();