Push only works with org.atmosphere.useBlocking=false

Hello all,

I have a working Application using 7.2.3 with Push enabled.
Now I am trying to rewrite the whole Application using 7.3.10 and Push.

But it’s only working in Firefox (35.0.1) and Internet Explorer (11) if I enable org.atmosphere.useBlocking in the web.xml.
Chrome is working without problems.

What are the downside when I use useBlocking? Why do I have to enable it? (In 7.2.3 it was working without it)

Thank you in advance.

Edit: I created a new test application using maven to test it out if maybe my new app is wrongly configured, but same behaviour.