// Declares that we're not following updates from this ProgressOperation anymore
    private void detach(ProgressOperation operation) {
        if (!isRenderable(operation)) {
            return;
        }

        unshow(operation);

        if (operation.getParent() != null && isRenderable(operation.getParent())) {
            attach(operation.getParent());
        } else if (!unassignedProgressOperations.isEmpty()) {