4.0 TitleHoverHandler seems to be in vain

(1). I attempted to add a TitleHoverHandler for the hover to pop up, but it seems not to catch the event.

(2). Using the same codes to test these libraries SmartGWT 3.0 and 4.0 respectively. 3.0 is ok, but 4.0 isn't.

(3). What should we do to solve this problem ??

Thanks.