Steps to Reproduce

http://zkfiddle.org/sample/rigvcs/3-scrollable-menubar-infinite-loop-in-zoomed-browser
Run fiddle.
Use browser zoom to : 110%
Scroll items in menubar

Current Result

After 1st click, menubar doesn't scroll.

Expected Result

Menubar should scroll regardless of zoom level

Debug Info

Caused by infinite loop in zul.menu.Menubar.prototype._moveTo
_moveTo is called on interval to update the position of the scrollable area.
if (currPos == moveDest) assume zoom level = 100% , and pixel = integer.
Since the values never match, the loop keep running and no futher scroll action is possible.

Root Cause

https://github.com/zkoss/zk/blob/5754625fdceec45f391123b46b1149b6a4e8e61b/zul/src/archive/web/js/zul/menu/Menubar.js#L254

Workaround