The horizontal scrollbar appears as expected but the focus jumps to the last columns.
This happens when the "selected"-property of a single item is set to "true".
So every time the listbox refreshes, the user must move the scrollbar back to the left.
This is on version 7.0.0, version 6.5.x works correct.
fiddle : http://zkfiddle.org/sample/itg49/1-Wide-listbox-scrolls-right-when-selecting-a-single-item