public void setProgress(final Progress progress) {
        this.progress = progress;
        if (progress != null) {
            update();
        }
    }
The progress bar maintains state of the highest seen upper bound
so that it can show the latest information about the source. This
resets that state.
stroom-core-client-widget/src/main/java/stroom/widget/progress/client/presenter/ProgressPresenter.java