Comment 2 for bug 774056

As Bryce says, the desired behaviour is to use permeable pointer barriers to briefly hold the cursor at the top and bottom of displays, as well as on the sides.
Please see the 'Top Bar and Global Menu-Targeting the Top Bar' section of the multi-monitor specification:
https://docs.google.com/a/canonical.com/document/d/1aHvJ-iIw-59bXTYBmIhQqEx0za2h9jpFE_RhZ2VOvJc/edit#bookmark=id.jcx28ut5mx5y