[11.10] previous viewport function not working properly in expo plugin

[Matt Baran]

After going to expo view (in my case standard 2x2 grid) the previous viewport binding which is by default bound to mouse wheel is not behaving as expected.
For comparison a "next viewport" button will change viewports in the same row, and go to the second row when it runs out of viewports, then back to the first row and so on.
However the "previous viewport" button will only change viewports in the same row and will not go to next/previous row like "next viewport" does.

This is only minor annoyance, and not very significant bug, however it feels like you can browse viewports only in "forward" direction, because browsing "backwards" is limited only to the row you're currently in.

System: Ubuntu 11.10
Package: compiz-plugins-main 1:0.9.6-0ubuntu4.2

Expected:
assuming viewports are numbered
1 2
3 4

I'm expecting to be able to move from viewport 3 to viewport 2 using previous viewport function.

What happens is viewport selection stays in viewport 3.
To move back to viewport 2 I have to use "next viewport" function through viewports 4,1,2 in opposite direction.