Bug 79916 [Viewers] isDisposed check needed in AbstractTreeViewer#internalRemove
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
: level - 1);
                    for (int i = 0; i < children.length; i++)
                        internalCollapseToLevel(children[i], nextLevel);
                }
            }
        }
    }
    /**
     * Recursively collects all expanded elements from the given widget.
     * 
     * @param result
     *           a list (element type: <code>Object</code>) into which to
     *           collect the elements
     * @param widget
     *           the widget
     */
    private void internalCollectExpanded(List result, Widget widget) {
        Item[] items = getChildren(widget);
        for (int i = 0; i < items.length; i++) {
            Item item = items[i];
            if (getExpanded(item)) {
                Object data = item.getData();
                if (data != null)
                    result.add(data);
            }
            internalCollectExpanded(result, item);
        }
    }
    /**
     * Tries to create a path of tree items for the given element. This method