Bug 299536 API refers to non-API type UIResourceFilterDescription
I20100112 CreateGroupOperation and CreateFolderOperation have constructors that require a UIResourceFilterDescription[]. However this is a non-API type, so clients can't reference it without using internals. Either the constructor should be removed or something like UIResourceFilterDescription needs to be promoted to API. Also, shouldn't CreateFolderOperation be renamed CreateVirtualFolderOperation?
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/undo/ContainerDescription.java
*         that is a leaf, or this container if there are no children.
	 */
	public ContainerDescription getFirstLeafFolder() {
		
		if (members == null || members.length == 0) {
			return this;
		}
		
		for (int i = 0; i < members.length; i++) {
			if (members[i] instanceof ContainerDescription) {
				return ((ContainerDescription) members[i]).getFirstLeafFolder();
			}
		}
		
		return this;
	}
	/**
	 * Add the specified resource description as a member of this resource
	 * description
	 * 
	 * @param member
	 *            the resource description considered a member of this
	 *            container.
	 */
	public void addMember(AbstractResourceDescription member) {
		if (members == null) {
			members = new AbstractResourceDescription[] { member };
		} else {
			AbstractResourceDescription[] expandedMembers = new AbstractResourceDescription[members.length + 1];
			System.arraycopy(members, 0, expandedMembers, 0, members.length);