In the arrowscrollbox binding, we're disabling a scroll button when there's no where to scroll in the direction it points to. We're updating its disabled state once the scrollbox overflows (at the same time we show the scroll buttons) and when the scrollbox is scrolled. However, we don't update its disabled state when the width of the boxObject of the scrollbox is changed, see bug 343585 for example. See bug 343585 comment 2 for a proposed solution.

(In reply to comment #0) > See bug 343585 comment 2 for a proposed solution. Well we can't add a 'box has changed size event' since that would require firing many events at a time, but it could be done by supporting a 'resize' event on the popup. Is that sufficient for this case?