Sliding menu is jumping?

I have used a basic jquery script to get the menu on my site to slide down and up.

When you click on the show/hide menu button, there is a little flash (Not a major issue) but when you close the slider, the page jumps up a little.

It looks a little glitchy?

Any ideas how I can fix that?

This is the code I am using



Sorry, I have found a solution to this. I moved the div containing the slider out of the wrapper and have it across the top of the page. Seems to work great outside the wrapping div.