Communication problem instead of session timeout

General
1

I have an issue with session timeout in Vaadin. Instead of showing the session timeout message, it shows me “communication problem” with my login.jsp (I used simple login.jsp for authorization).
Maybe it has something in common with widgetset addons?

Here is the debug output from client side debug

Communication error: (SyntaxError): XML tag name mismatch (expected link) stack: zV@http://localhost:8080/VAADIN/widgetsets/com.vaadin.terminal.gwt.DefaultWidgetSet/CBF9DC5091288C6257657899E893380C.cache.html:1768 
MV@http://localhost:8080/VAADIN/widgetsets/com.vaadin.terminal.gwt.DefaultWidgetSet/CBF9DC5091288C6257657899E893380C.cache.html:3200 
rm@http://localhost:8080/VAADIN/widgetsets/com.vaadin.terminal.gwt.DefaultWidgetSet/CBF9DC5091288C6257657899E893380C.cache.html:2431 
Rm@http://localhost:8080/VAADIN/widgetsets/com.vaadin.terminal.gwt.DefaultWidgetSet/CBF9DC5091288C6257657899E893380C.cache.html:3197 
@http://localhost:8080/VAADIN/widgetsets/com.vaadin.terminal.gwt.DefaultWidgetSet/CBF9DC5091288C6257657899E893380C.cache.html:1742 
Rb@http://localhost:8080/VAADIN/widgetsets/com.vaadin.terminal.gwt.DefaultWidgetSet/CBF9DC5091288C6257657899E893380C.cache.html:1370 
Ub@http://localhost:8080/VAADIN/widgetsets/com.vaadin.terminal.gwt.DefaultWidgetSet/CBF9DC5091288C6257657899E893380C.cache.html:2675 
@http://localhost:8080/VAADIN/widgetsets/com.vaadin.terminal.gwt.DefaultWidgetSet/CBF9DC5091288C6257657899E893380C.cache.html:1895 
fileName: http://localhost:8080/VAADIN/widgetsets/com.vaadin.terminal.gwt.DefaultWidgetSet/CBF9DC5091288C6257657899E893380C.cache.html lineNumber: 1771 - Original JSON-text:head>

Could you please help?