Flickering menus

we’ve got some pretty annoying flickering in our menus which is preventing users from being able to select different views – i.e. week, month etc

I’ve recorded a video to show the problem – http://www.youtube.com/watch?v=OVj38H2uWXU

Could anyone shed some light on why it’s happening or how i can debug it in firefox/firebug

The same thing is happening on FF Safari and Chrome.

Thanks,

James

http://wordpress.org/extend/plugins/all-in-one-event-calendar/