run the example on an iphone5 or iphone5 emulation on chrome.
click the buttons in sequence 1. -> 2.

an error in the JS console appears

Uncaught ReferenceError: bar is not defined borderlayout-on-mobile-workaround.zul:68
zk.override.onChildRemoved_ borderlayout-on-mobile-workaround.zul:68
zk.Widget.zk.$extends.removeChild zk.wpd:14801
zk.Widget.zk.$extends.detach zk.wpd:14806
zAu.cmd1.rm zk.wpd:19259
doProcess zk.wpd:18269
doCmdsNow zk.wpd:18512
zAu._doCmds zk.wpd:18752
afterResponse zk.wpd:18401
onResponseReady