Latest Xfdesktop SVN places some (minimized window) icons on top of each other,
in the top left corner of the icon grid. It seems to happen when the first
column is filled with icons, all subsequent icons will be placed in the top left
corner of the grid.

Reproducible: Always
Steps to Reproduce:
1. Open more minimizeable windows on the current workspace than the number of
rows in the Xfdesktop icon grid.
2. Minimize all the opened windows, eventually by pressing Ctrl+Alt+D (Xfwm4
shortcut to show desktop).
Actual Results:  
The first column in the icon grid is filled with icons, all following icons are
placed on top of the top left icon.

Expected Results:  
Xfdesktop should use the subsequent columns for subsequent icons.

I'm running Xfce SVN in Ubuntu 5.10 with GTK+ 2.8.6.