To Saïvann and Oliver: I also think that this bug is /not/ a duplicate of bug #175986 because here, the aim is to _add_ the feature of changing the viewport by scrolling the mouse wheel over the Desktop Switcher whereas the other issue is to _change the default to "disabled"_ of the feature of changing the viewport by scrolling the mouse wheel over the Desktop Background.
No, this is unfortunately not fixed in Hardy.
To Saïvann and Oliver: I also think that this bug is /not/ a duplicate of bug #175986 because here, the aim is to _add_ the feature of changing the viewport by scrolling the mouse wheel over the Desktop Switcher whereas the other issue is to _change the default to "disabled"_ of the feature of changing the viewport by scrolling the mouse wheel over the Desktop Background.