private void updateAddFromAllTagsEnabledState() {
        addFromAllTagsButton.setEnabled(allTagsListBox.getItemCount() > 0
                && allTagsListBox.getSelectedIndex() != -1);
    }
@return Trimmed and lower-cased tag.
stroom-core-client/src/main/java/stroom/explorer/client/view/ExplorerNodeEditTagsViewImpl.java