private void handleFailure(final RestError t) {
        AlertEvent.fireError(
                ExplorerNodeEditTagsPresenter.this,
                t.getMessage(),
                null);
    }
Presenter for editing the tags on a single node or adding tags to multiple nodes.
See {@link ExplorerNodeRemoveTagsPresenter} for tag removal on multiple nodes.
stroom-core-client/src/main/java/stroom/explorer/client/presenter/ExplorerNodeEditTagsPresenter.java