Task board gadget cannot display more than four columns

Task board gadget cannot display more than four columns on a dashboard. The same problem applies to the Wallboard view.

We have configured five GreenHopper columns (To Do, In Progress, Resolved, Testing, Done). However, task board gadget does not display the fifth column (Done), in any layout configuration. Please see attached screenshot. That column also cannot be displayed on Wallboard, even in full screen view, and using a browser's zoom out feature. We have tried to fix this view using multiple browsers (Firefox, Chrome, IE, Opera...), but it simply does not work. Therefore, we are not able to use Wallboard plugin using all five columns.

Column width should probably be auto-resizable, or an administrator should be able to configure it as a parameter.