Post all the code is really bizzare (1200 line more or less) so I create a fiddle for this.
The whole page is really slow, also when I try to manage items on the DOM with Firebugs or others tools (it’s really frozen).
So I think the best way is to optimize the HTML-CSS (in fact, removing the CSS definition the page back really faster).
I don’t speak about loading the page, but navigate/edit item when the page is loaded (really, try to sort it out with firebug for example, you will see immediatly; you will notice it also on fiddle too).
Instead of having everything editable at once, only go in editing mode once you click an edit link for the row (asp.net style) or when you click on the row itself (devexpress style), and only then show your editing stuff for that row only.
The easiest way to make pages faster is to remove the controls from it 🙂