Looks like there's an issue with the pb626fw5 skin.
When you call a menu setting and set a value on the last page, you afterwards can't set a value on an earlier page further than items available on the last page of this menu item.
Confusing? You won't be after the next episode of Soap
Suppose you have 3 pages of fonts and the last page contains 4 items; when you select on of the fonts on the last page you can't select another font on page 1 or 2 beyond the first four fonts at either page. When you exit Cool Reader solves the issue: afterwards you can select all fonts again...