WebList box problems

Having loads of troubles with the WebListbox. Sometimes the “Show 25 entries” selector appears in the upper left corner, and sometimes not. What determines when this selector is shown?
When I have ± 50 rows, the selector starts with 25, but no rows are visible. There is data in the ListBox, and after I switch the select to 10 lines, I see 10 lines. If I click on the paging in the lower right corner, nothing happens and the Listbox only shows the first 10 lines.
Is there a way the ListBox does not use the “Show … entries” selector?

If you are seeing that control, a JavaScript exception has occurred while the table was refreshing. A bug report with a sample project would be helpful in this regard.