I'm using Maxthon PC 4.4.8. Each time I drag-drop a label to a mail title in Gmail. Maxthon will open a new page tab with same gmail url as the original one. If I drag-drop 5 times, it will 5 page tab with same gmail urll. In other browsers, e.g. Chrome, Firefox or IE, this doesn't happened. What's wrong and how to fix it?