[Plugin: Events Calendar] Tooltip flickers when it appears above calendar title

Hi,
I am using the Events Calendar on a page on my website – http://www.distracted.com.au/datebook/

When the tooltip appears below the calendar entry, everything works correctly.
But, when you make the browser window smaller, this somehow forces the bigger tooltip entries to appear above the calendar entry title, and the tooltip starts to flicker as you move your cursor.

Is there any way to alway force the tooltip to appear below the title?

Any help would be appreciated.

Thanks!
Jenny