This was claimed to cause problems for Chromium, see bug 599130.

Also work around apparent rounding errors in XIWarpDevice by
setting the 'small step' for keynav dnd to 2 instead of 1 - I notice
that a warp seems to sometimes warp a little less than I tell it to,
and if I tell it to only move by 1 pixel then moving less means
that you are stuck.