Non-smooth scrolling pdf with trackpad in Preview with 10.8

[FrenchKheldar]

Finally upgraded to Mountain Lion and I am noticing an annoying behavior in Preview. When I two-finger scroll too quickly with my 2009 MBP trackpad, the scrolling is jerky and can skip many pages in a document. So you're scrolling a 25 page document, you are at page 2, you scroll quickly to get to page 10 and suddenly you are page 22...

I cannot replicate this with a mouse no matter how fast I scroll and I don't see a setting for trackpad scrolling speed. Slowing down the tracking speed of the trackpad seems to have no effect either... I have secrets installed but I can't find a hidden preference there either... Anyone else experiencing this? How could I fix this?

Thanks in advance !

EDIT: I also had the smooth scrolling disabled (thanks John Siracusa!) via

defaults write -g NSScrollAnimationEnabled -bool NO

but turning this back on has no effect on this behavior.

My setup: 2009 13" MBP with 10.8.2. Full disclosure, this is a cross-post from StackExchange.

[sshhoott]

Originally Posted by FrenchKheldar

Finally upgraded to Mountain Lion and I am noticing an annoying behavior in Preview. When I two-finger scroll too quickly with my 2009 MBP trackpad, the scrolling is jerky and can skip many pages in a document. So you're scrolling a 25 page document, you are at page 2, you scroll quickly to get to page 10 and suddenly you are page 22...

I cannot replicate this with a mouse no matter how fast I scroll and I don't see a setting for trackpad scrolling speed. Slowing down the tracking speed of the trackpad seems to have no effect either... I have secrets installed but I can't find a hidden preference there either... Anyone else experiencing this? How could I fix this?

Thanks in advance !

EDIT: I also had the smooth scrolling disabled (thanks John Siracusa!) via but turning this back on has no effect on this behavior.

My setup: 2009 13" MBP with 10.8.2. Full disclosure, this is a cross-post from StackExchange.

Try opening that PDF document in Safari. Safari has a much smoother hardware accelerated scrolling engine. (Right click on PDF file > open with > Safari)

From what I observed, if you scroll crazy fast on the trackpad, it keeps on accelerating and accelerating until it reaches the end of a long PDF document. The user tends to miss a lot of pages scrolling this way. I guess the only way to scroll without missing pages is to have some pause in between when you lift your fingers from the bottom of the trackpad and place them on top of the trackpad during scrolling. I hope that made sense, but do try using Safari. Cheers.