Normally, we set the "immediate" attribute on any buttons that cancel the current operation. For obvious reasons, we need to bypass the validation process when any such button is pressed. The flow is basically this:

Porlet X -> Initial view A -> User selects option -> Selected view B -> User presses "Cancel" -> Returned to view A

If the "immediate" attribute on the "Cancel" button in view B is left out (or set to false), this is what shows up in the Chrome network monitor (assuming I fill in data that satisfies the validation requirements):

http://localhost:8080/home?p_p_id=session_manager_WAR_Gateway&p_p_lifecycle=2&p_p_state=normal&p_p_mode=view&p_p_cacheability=cacheLevelPage&p_p_col_id=column-1&p_p_col_count=1&_session_manager_WAR_Gateway__jsfBridgeAjax=true&_session_manager_WAR_Gateway__facesViewIdResource=%2Fsession%2Flogin.xhtml

If the "immediate" attribute is set to "true", this is what shows up:

http://localhost:8080/home?p_p_id=session_manager_WAR_Gateway&p_p_lifecycle=2&p_p_state=normal&p_p_mode=view&p_p_cacheability=cacheLevelPage&p_p_col_id=column-1&p_p_col_count=1&_session_manager_WAR_Gateway__jsfBridgeAjax=true&_session_manager_WAR_Gateway__facesViewIdResource=%2Fsession%2Flogin.xhtml
http://localhost:8080/home?p_p_id=session_manager_WAR_Gateway&p_p_lifecycle=2&p_p_state=normal&p_p_mode=view&p_p_cacheability=cacheLevelPage&p_p_col_id=column-1&p_p_col_count=1&_session_manager_WAR_Gateway_javax.faces.resource=jsf.js&_session_manager_WAR_Gateway_ln=javax.faces
http://localhost:8080/home?p_p_id=session_manager_WAR_Gateway&p_p_lifecycle=2&p_p_state=normal&p_p_mode=view&p_p_cacheability=cacheLevelPage&p_p_col_id=column-1&p_p_col_count=1&_session_manager_WAR_Gateway_javax.faces.resource=bridge.js&_session_manager_WAR_Gateway_ln=ice.core
http://localhost:8080/home?p_p_id=session_manager_WAR_Gateway&p_p_lifecycle=2&p_p_state=normal&p_p_mode=view&p_p_cacheability=cacheLevelPage&p_p_col_id=column-1&p_p_col_count=1&_session_manager_WAR_Gateway_javax.faces.resource=util%2Face-jquery.js&_session_manager_WAR_Gateway_ln=icefaces.ace
http://localhost:8080/home?p_p_id=session_manager_WAR_Gateway&p_p_lifecycle=2&p_p_state=normal&p_p_mode=view&p_p_cacheability=cacheLevelPage&p_p_col_id=column-1&p_p_col_count=1&_session_manager_WAR_Gateway_javax.faces.resource=compat.js&_session_manager_WAR_Gateway_ln=ice.compat
http://localhost:8080/home?p_p_id=session_manager_WAR_Gateway&p_p_lifecycle=2&p_p_state=normal&p_p_mode=view&p_p_cacheability=cacheLevelPage&p_p_col_id=column-1&p_p_col_count=1&_session_manager_WAR_Gateway_javax.faces.resource=util%2Face-components.js&_session_manager_WAR_Gateway_ln=icefaces.ace
http://localhost:8080/home?p_p_id=session_manager_WAR_Gateway&p_p_lifecycle=2&p_p_state=normal&p_p_mode=view&p_p_cacheability=cacheLevelPage&p_p_col_id=column-1&p_p_col_count=1&_session_manager_WAR_Gateway_javax.faces.resource=icefaces-compat.js&_session_manager_WAR_Gateway_ln=ice.compat
http://localhost:8080/home?p_p_id=session_manager_WAR_Gateway&p_p_lifecycle=2&p_p_state=normal&p_p_mode=view&p_p_cacheability=cacheLevelPage&p_p_col_id=column-1&p_p_col_count=1&_session_manager_WAR_Gateway_javax.faces.resource=util%2Face-menu.js&_session_manager_WAR_Gateway_ln=icefaces.ace

Note that "localhost" is mapped to an organization site in Liferay.

The first line in the "immediate" true case is the same as the line in the false case. The subsequent lines have several problems.

Problem 1: There's no logical reason for all this extra traffic. Pressing the button in the false case sends only a single request/response; pressing the button in the true case isn't doing anything more from an application perspective so the extra traffic is completely unwarranted.

Problem 2: The first line is properly encoded. The second line has the query parameters escaped, with '&" replaced with "&"; this thoroughly messes things up for Liferay.

Problem 3: As a result of problem 2, bean management goes to hell in a handbasket. All of our beans use @CustomScoped("#{window}") and tracking the constructor for the bean in view A shows that it's being called multiple times, once for each request other than the first one. Deep inspection of the bean map in the window scope shows that a different window map is being created for each request (hardly surprising given the mess of the URLs). This, naturally, has an impact on application functionality as well as on its performance (the constructors often have side effects such as loading data from the database).

Although we're using ICEfaces for the bulk of our components, the problem occurs whether we use <ace:pushButton> or <h:commandButton> to cancel view B; it's the "immediate" attribute that is causing the grief.