If you have a large listbox with paging and try to navigate using the page up/down keys, the system throws an "Out of bound" exception in the last page.
Please see attached zul/controller to reproduce the problem.
1. At the first page of the listbox select the last shown record.
2. Start pressing page down until you reach the last page.
3. Right before the last page the system throws the 'Out of bound' exeption.