Master/Details scenario: how to update the details table without loosing the selection in SWT?

Hello,

I have 2 GL table viewers in SWT. I periodically refresh the master view and the details view. If the master viewer is updated (using replaceAllSorted) it also triggers a refresh of the details view for the currently selected item. The details view then does a clear() and addAll() with its list. This looses the selection of course. Using replaceAllSorted in the details makes it updating weird. Old entries stay in the list for a visible amount of time. The details list items implement Comparable.

please find my update code below:
public void selectionChanged(final IFormPart part, final ISelection selection) {
                if (!(selection instanceof StructuredSelection)) {
                        return;
                }
                this.positions.getReadWriteLock().writeLock().lock();
                try {
                        this.positions.clear();
                } finally {
                        this.positions.getReadWriteLock().writeLock().unlock();
                }

                final OrderService orderService = (OrderService) this.orderServiceTracker.getService();
                if (orderService != null) {
                        final Iterator<Order> iterator = ((StructuredSelection) selection).iterator();
                        while (iterator.hasNext()) {
                                final Order order = iterator.next();
                                final Collection<LineItem> newPositions = orderService.getPositions(order.getOrderNumber());
                                this.positions.getReadWriteLock().writeLock().lock();
                                try {
                                        this.positions.addAll(newPositions);
                                        this.form.setText(NLS.bind(Messages.OrderDetailsPage_Positions, this.positions.size()));
                                } finally {
                                        this.positions.getReadWriteLock().writeLock().unlock();
                                }
                                // Do not show all orders. This should be later enabled by the user using a toolbar button.
                                break;
                        }
                }
        }