Swipe sometimes work
Strangely enough, two-finger sideways swipe works like a charm in LaunchPad but not in Safari or any other places. In Safari, the two-finger sideways swipe is somehow recognized as different from a one-finger swipe (or it could simply be that the system when seeing two-finger sideways sends events which are ignored by Safari), since the pointer stays still when this gesture is used.
The only way this could conceivably happen would be if the "3 and more" touch gestures have another API than the two-touch, and Launchpad is capable of using both while Safari uses only the newer one. Will be interesting to see if Apple will bother to fix it for legacy users..