GWT serialization problem

Hello, in my app I faced a problem when reloading some pages. The error is: com.google.gwt.user.client.rpc.SerializationException: java.lang.RuntimeException: Unable to find class com.google.gwt.user.client.rpc.core.java.lang.Long_FieldSerializer I've downloaded gwt sources and found that

Refresh button hangs up GWT application

I have a problem with my GWT (2.5.0) app: on some (not all) pages when user hits refresh or F5 button, my app stops responding and only shows loading wheel. For example, on page http://127.0.0.1:/portal/index.html?gwt.codesvr=127.0.0.1:9997#categories refresh works fine, but on