    dfn.classList.add('has-dfn-panel');
    dfn.addEventListener('click', (event) => {
        toggleDfnPanel(dfn);
        event.stopPropagation();
    });
    dfn.addEventListener('keypress', (event) => {
        const kc = event.keyCode;
        // 32->Space, 13->Enter
        if(kc == 32 || kc == 13) {
            toggleDfnPanel(dfn);
            event.stopPropagation();
            event.preventDefault();
        }
    });
}

function refocusOnTarget(event) {
    const target = event.target;
    setTim