Sub-menu in primary navigation menu

As I move my cursor with my mouse from a sub-category in the primary navigation menu to another category in the primary navigation menu it does not appear to transition to the next category. The only way to move to another category is to move the cursor away from the entire menu so the sub-category is deselected.

Any quick ideas to fix this? I like the template, but this issue is irritating enough that I will likely download a new one.