With ZK 8.6.0.1 (iceblue theme), the top border line has moved from z-tabpanels to z-tabpanel, which causes flex height issue if browser (chrome) applies zooming

http://zkfiddle.org/sample/32f5ike/4-Collapsible-borderlayout

In above example, style="overflow-y: auto" shows scrollbar, because tabpanel content height exceeds calculated tabpanel height if chrome zoom level is 90% (see screenshots)! In ZK 8.5 the flex height was calculated in correct way!