add delay before displaying drop-down menu

Issue Summary

passing the mouse over simplemenu always trigger a drop-down, even when i am doing other stuff, like trying to access a browser menu, or a browser tab. this is very counter-productive and distracting.

is there any way to add a very small delay before a drop-down is displayed?

if you tell me where to get started, i will implement you and provide a patch. thanks, Renaud