Bug 184755 [DataBinding] internal tree content provider does not work
I broke the tree content providers while trying to update them to use TreePaths. It would be good to have a working implementation again...
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/internal/databinding/internal/viewers/OrderedTreeNode.java
public void addParent(Object parent) {
		if (this.parent == null) {
			this.parent = parent;
		} else {
			if (parent.equals(this.parent)) {
				return;
			}
			if (parents == null) {
				parents = new HashSet();
				parents.add(this.parent);
			}
			parents.add(parent);
		}
	}
	/**
	 * @param parent
	 */
	public void removeParent(Object parent) {
		if (this.parents != null) {
			parents.remove(parent);
		}
		if (parent == this.parent) {
			if (parents == null || parents.isEmpty()) {
				this.parent = null;
			} else {
				this.parent = parents.iterator().next();
			}
		}
		if (this.parents != null && this.parents.size() <= 1) {
			this.parents = null;