Bug 292322 [Viewers] Tree view is removing + indicator when one of multiple children is removed.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java
this(new Tree(parent, style));
	}
	/**
	 * Creates a tree viewer on the given tree control. The viewer has no input,
	 * no content provider, a default label provider, no sorter, and no filters.
	 *
	 * @param tree
	 *            the tree control
	 */
	public TreeViewer(Tree tree) {
		super();
		this.tree = tree;
		hookControl(tree);
	}
	/*
	 * (non-Javadoc) Method declared in AbstractTreeViewer.
	 */
	protected void addTreeListener(Control c, TreeListener listener) {
		((Tree) c).addTreeListener(listener);
	}
	/*
	 * (non-Javadoc)
	 *
	 * @see org.eclipse.jface.viewers.ColumnViewer#getColumnViewerOwner(int)
	 */
	protected Widget getColumnViewerOwner(int columnIndex) {
		if (columnIndex < 0 || ( columnIndex > 0 && columnIndex >= getTree().getColumnCount() ) ) {
			return null;
		}
		if (getTree().getColumnCount() == 0)