Webstorm 9 OSX - smooth scrolling is not

Running Webstrom 9 on Yosemite and could swear that scrolling in the editor using the trackpad was smooth in Webstorm 8 but is now rather jerky.
It seems to be scrolling at least on line of code at a time if I go really slowly and changing the "smooth scrolling" option in preferences has no effect.

Interestingly dragging the scrollbar in the right side of the editor does not do the one-line-at-a-time scrolling but still does not seems very smooth - it almost looks like the framerate of the actual editor i low.

Any ideas ?

Best regards
Morten Olsson