stamen/modestmaps-js — comment on commit 1e21b70481fbb991cc280127e90eff45de5d1dfd
File:  line 0
By RandomEtc:

@shawnbot / @tmcw there's a regression in the anyscale example. If you do a two fingered swipe up or down in Safari on Mac OS Lion then the momentum scrolling gets interrupted as new tiles appear. It should continue to scroll smoothly.

This happens at the time of writing on
http://prag.ma/code/modestmaps-js/examples/anyscale/

If you check out and test this version where I last fixed the issue, hopefully you can tell the difference (I admit it's a subtle one!) :)
https://github.com/stamen/modestmaps-js/commit/f59147036f06586feab82e0b8f39f5979c4888ea

The fix there was to add a new div that is dedicated to receiving mousewheel events. Not sure if that breaks other recent additions but it should be safe (and might also be useful for listening for clicks/drags on the map without having tiles get in the way?). It might need adjusting to always be on top of the other layers, not sure.