Steps to Reproduce

run the attached example

./gradlew startJettyRunner

http://localhost:8080/wpd-race/

wait for components/widgets to be added/render dynamically via server push

Current Result

while components/widgets render as expected
-> related wpd files are loaded on demand, when widgets are instantiated
-> JS ERROR happens when a JS method is invoked on the 4th widget, too early

zk.wpd:30474 Uncaught TypeError: Cannot read property 'apply' of undefined
    at Object.invoke (zk.wpd:30474)
    at doProcess (zk.wpd:28681)
    at zk.wpd:28643
    at Function.zk.afterMount (zk.wpd:26916)
    at dataNotReady (zk.wpd:28638)
    at doProcess (zk.wpd:28651)
    at doCmdsNow (zk.wpd:28780)
    at Object._doCmds (zk.wpd:29144)
    at mtAU0 (zk.wpd:27086)
    at doEnd (zk.wpd:26472)

Expected Result

no JS error, invoking JS on a component that's still being rendered should wait for it to become available

Debug Information

the example used a fixed delay to simulate network latency in zk.support.debug.MyWpdExtendlet

This can be changed in zk.support.debug.WdpRaceComposer
If too small the problem will occur less predictable.

there are 2 ways to cause a problem (2nd commented out in the composer)

1. Clients.response(new AuInvoke(component, "setStyle", "color: green;")); //causes client side error
2. ((HtmlBasedComponent)test).setStyle("color: green"); //silently fails at client side

Workaround