private void updateClearInputVisibleState() {
        final boolean isInputEmpty = NullSafe.isEmptyString(textBox.getText());
        clearInputButton.setVisible(!isInputEmpty);
        final String text = "All known tags"
                + (isInputEmpty
                ? ""
                : " (filtered)");
        allTagsFormGroup.setLabel(text);
    }
@return Trimmed and lower-cased tag.
stroom-core-client/src/main/java/stroom/explorer/client/view/ExplorerNodeEditTagsViewImpl.java