Luis,
I understand your frustration with the behavior with regard to scrolling the LAB, but the problem is most likely with your browser on your computer. I used to have that problem, but switched browsers and now I am rather pleased. For example on my Mac (I realize you may have windows, but this example still holds as well an example) I have the following web browsers:
Internet Explorer, my previous browser of choice, how ever it always performed exactly as you described, never remembering my scroll location when using back/forward functions
Safari, my new browser of choice, which will remember the scroll location, although it does a rather odd job of it, always displaying the top of the page, and then perhaps taking up to a second to jump to the correct scroll point.
Camino, which does an excellent job of most things, always jumps instantly to the correct scroll point when using the back/forward functions.
Hope this helps some.
-Mikey P