Bug 125272 [Viewers] AbstractTreeViewer needs remove(Object parentElement, Object[] childElements)
There is an add(Object parentElement, Object[] childElements) but no corresponding remove(). Without this method, if you have an element that appears under multiple parents, the only way to get model and viewer in sync after removing the element from just one of its parents is calling refresh().
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
Object data = items[mid].getData();
            int compare = sorter.compare(this, data, element);
            if (compare == 0) {
                
                while (compare == 0) {
                    ++mid;
                    if (mid >= count) {
                        break;
                    }
                    data = items[mid].getData();
                    compare = sorter.compare(this, data, element);
                }
                return mid;
            }
            if (compare < 0)
                min = mid + 1;
            else
                max = mid - 1;
        }
        return min;
    }
    /**
     * Adds the given child element to this viewer as a child of the given
     * parent element. If this viewer does not have a sorter, the element is
     * added at the end of the parent's list of children; otherwise, the
     * element is inserted at the appropriate position.
     * <p>
     * This method should be called (by the content provider) when a single
     * element has been added to the model, in order to cause the viewer to
     * accurately reflect the model. This method only affects the viewer, not