When you use the list dividers from the documentation inside a inset list, the framework doesn't consider the special classes for the first and the last li-item. (which are used for the rounded borders)
Hence, when I type a search phrase, which disables the first or the last li-item, the rounded borders-effect of the inset list disappears.
Suggested solution: Use css3 pseudo-classes first-child and last-child instead of real classes for rounded borders?
In addition to the first li getting ui-corner-top, the .ui-li-link-alt gets ui-corner-tr and .ui-li-thumb gets ui-corner-tl. There are the reverse rules for the last li in the list. The CSS might get complex because it the first-child that is not(ui-screen-hidden) where you have to apply all three rules.
Fix for issue #1450: added refreshCorners method to listview widget