Comment 45 for bug 1240957

> This bug isn't about switching workspaces with scroll events

Well, it used to happen only with that configuration, it seems like things changed. It might be because unity grabs those events to use them when you scroll over launcher icons

> This bug is also a regression from Ubuntu 12.04.. so might be more important if you have a bunch of 12.04 LTS users upgrading next month.

It's already important, but if you read the upstream comment it's not an easy to fix one...