Main menu drop down function not working

Hello,

When I hover the cursor over the drop down menu all of the subcategories expand as well. When I first created it, the subcategories would only expend when the cursor was hovering over each section and close once you moved the cursor away. I don’t know if this changed with a recent update, or if there is a conflict in the code somewhere.

Below is a screenshot of the menu.

https://www.dropbox.com/s/mlbuwrzc1yj8edr/Screenshot%202015-03-31%2013.15.59.png?dl=0