jQuery slide jumps around on some divs

[cocoreeco]

I am building a little website so here is my problem :I've got a first header div which contains header stuff. It has position relative and stuff inside is position absolute, but I think that we don't really care about this one.Just below I've got my main container div with no defined positioning and some \[code\]<h1>\[/code\] and \[code\]<p>\[/code\] in it. Each \[code\]h1\[/code\], on click, opens some content below with jQuery slide.This is the code. The sliding part is\[code\]$("#container_" + tabName).slideToggle\[/code\]The point is that on the which i called "buggy" in the example, and also on all other in my dev version, the jQuery slide is jumpy at the beginning and end of the animation.I've done some search I found that I had to put a defined width but it didn't change anything.. Tried a lot of stuff already but I really don't find how to do that.