UI slide effect toggle

UI slide effect toggle

I have a simple <ul> that i want to .show("slide") trigered via .hover() of another <ul> .
If I slowly put the mousein, and let the effect to finish its slide and then i mouseout from the <ul> everything worked. But if i fast crossed the <ul> so the effect doesn't finish the slide, then it never hide.

I put a little debug in the code, and examined, that both mousein and mouseout are fired, but the second slide effect doesn't execute if another effect is in progress on that same object ???????