the L521x drivers clearly have a problem when any two finger scrolling can cause the document in any program to immediately skip to the very beginning or the very end.
This issue has come up in the thread http://en.community.dell.com/support-forums/laptop/f/3518/t/19490876.aspx but that has been incorrectly marked as answered and I'm concerned that the issue will be buried because of that.
Synaptics have released several driver versions since the 126.96.36.199 driver, up to 188.8.131.52, fixing many issues including a BSOD, whereas so far for the L521x we have just had A03 and A04 variants of the same driver (184.108.40.206), neither of which solve this problem.
Please could you push the release of a newer driver for us, or supply us with a means to install the Synaptics generic drivers from http://www.synaptics.com/resources/drivers if we so wish.
As it stands the touchpad is incredibly frustrating to the point of it being completely unusable to work with, a return of the machine for refund would be shortly sought by most if the issue cannot be rapidly addressed..
Newest drivers from synaptics website are now SIGNED!
These installed for me immediately without issue, no modification to current OS settings, and the bounce problem has not returned after a reboot.
I am experiencing the same the symptoms with my xps 14 ultrabook.
I've uninstalled and reinstalled the touchpad drivers, using both the A03 and A04 drivers.
Two finger scrolling will intermittently cause the page I am working in to jump to top or to the bottom, regardless of program e.g. MS Office, Chrome, Internet Explorer...etc.