Comment 3 for bug 776074

the same happens with upper and lower workspaces, not just with left and right borders.

1) go to the bottom-left workspace
2) open gedit (or another program) and drag it to the left so that it takes the half of your screen
3) go to top-left workspace
4) click on the gedit icon in the launcher

what you will see:

1) the workspace wil not change
2) gedit will drop a few pixels and you will see the bottom border of gedit on the top-left workspace. So to go to gedit afterwards, you need to go to workspace 3 and you need to drag gedit a few pixels up again.