 Returns the time (in ms) during which {@link #getQuickOpenDelay()} should
     * be used instead of {@link #getOpenDelay()}. The quick open delay is used
     * when the tooltip has very recently been shown, is currently hidden but
     * about to be shown again.
 Returns the time (in ms) during which {@link #getQuickOpenDelay()} should
     * be used instead of {@link #getOpenDelay()}. The quick open delay is used
     * when the tooltip has very recently been shown, is currently hidden but
     * about to be shown again. | VTooltip.java