Steps to Reproduce

Run the attachment (frozen-performance-no-patch.zul) and use the horizontal scrollbar.

Actual Result

in Chrome it is noticeably slower to scroll to the right (scrolling back to the left is smooth)
IE11 has an overall terrible scroll performance

Expected Result

Better performance, at least consistent speed between left and right scrolling

Debug Info

https://www.sitepoint.com/10-ways-minimize-reflows-improve-performance/
the steps 6, 7 and 9 described in the document help to reduce the number of CSS reflows
by batching the updates onto hidden DOM elements, and by throttling highly frequent (smooth) scroll events causing additional overhead (esp in IE)

Root Cause

the updating loop in Frozen._doScrollNow (Line 329ff) performs both, css updates and reads offsetWidth of affected elements, resulting in repeated reflows, those updates can be batched and performed in the end (while hiding the mesh during the update batch)

the method Frozen._doScroll can throttle high frequent smooth scroll events to avoid additional overhead

both ideas are implemented in frozen-performance-patch.js and the significant performance difference can be observed in frozen-performance.zul

Workaround

apply the patch to affected pages:
<?script src="frozen-performance-patch.js"?>