when I move cursor from bottom (of menu list) to right-top content of menu disappearing.
I guess it happens because of not adjusted time in JS. but may be other reason.
this is very annoying problem.
I have test your site. I move the cursor from bottom (of menu list) to the right-top content of menu and its not disappearing and all of your mega menus working just fine. It only disappears when the pointer goes outside the box because it is designed in this way that if the pointer goes outside the box then box will hidden otherwise it will be shown. I also try to move cursor fast and its working just fine as expected.
As I mentioned in my previous reply, It only disappears when the pointer goes outside the box because it is designed in this way that if the pointer goes outside the box then box will hidden otherwise it will be shown. I also test the left-top (near the border of left menu (column)).