I'm seeing the same issue as Christian in Ubuntu 13.10 (Saucy) updated as of last night.
Issue seems to be Document Viewer (evince?) and gedit only so far.... -- You received this bug notification because you are a member of DX Packages, which is subscribed to unity in Ubuntu. Matching subscriptions: dx-packages https://bugs.launchpad.net/bugs/1171342 Title: mouse scroll wheel not working in gedit & System Monitor Status in “unity” package in Ubuntu: Confirmed Bug description: Open System Monitor Using mouse wheel button - scroll up or down - list does not move. If Press the wheel button and then scroll up or down the list will move. This also occurs in Gedit. Firefox and Terminal work as expected. IE do not need to press the wheel and then scroll Linux kylea-hpxt 3.8.0-19-generic #29-Ubuntu SMP Wed Apr 17 18:16:28 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux Description: Ubuntu 13.04 Release: 13.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/unity/+bug/1171342/+subscriptions -- Mailing list: https://launchpad.net/~dx-packages Post to : dx-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~dx-packages More help : https://help.launchpad.net/ListHelp