I took blog example from Seam 2.0.1 CR and had builtin vars resolved.
Please note tag, that IDEA creates builtin variables on analysis of components.xml e.g.
identity variable is added when components.xml has tag <security:identity />
localSelector variable is added upon presence of <core:resource-loader/> in the same config file

I use this components.xml file:

<?xml version="1.0" encoding="UTF-8"?>

<components xmlns="http://jboss.com/products/seam/components"
xmlns:core="http://jboss.com/products/seam/core"
xmlns:mail="http://jboss.com/products/seam/mail"
xmlns:security="http://jboss.com/products/seam/security"
xmlns:web="http://jboss.com/products/seam/web"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://jboss.com/products/seam/components http://jboss.com/products/seam/components-2.0.xsd
http://jboss.com/products/seam/core http://jboss.com/products/seam/core-2.0.xsd
http://jboss.com/products/seam/mail http://jboss.com/products/seam/mail-2.0.xsd
http://jboss.com/products/seam/security http://jboss.com/products/seam/security-2.0.xsd
http://jboss.com/products/seam/web http://jboss.com/products/seam/web-2.0.xsd">
<core:init debug="true" jndi-pattern="sine/#{ejbName}/local" transaction-management-enabled="false"/>

<core:manager conversation-timeout="120000" conversation-id-parameter="cid"/>

<core:resource-loader>
<core:bundle-names>
<value>sine</value>
<value>messages</value>
</core:bundle-names>
</core:resource-loader>

<security:identity authenticate-method="#{authenticatorService.authenticate}"/>
<mail:mail-session session-jndi-name="java:/Mail"/>

<web:character-encoding-filter encoding="UTF-8" override-client="true" url-pattern="*.jspx"/>
<web:redirect-filter url-pattern="*.jspx"/>
<!--<web:multipart-filter create-temp-files="false" max-request-size="524288" url-pattern="*.jspx"/>-->
<web:multipart-filter create-temp-files="false" url-pattern="*.jspx"/>
<web:exception-filter url-pattern="*.jspx"/>
</components>

and as I mentioned in IDEA-41497 IDEA only resolves some of the builtin (also custom) methods.
This is really strange if it works for you and not for me :-(

Does IDEA highlight following file properly?
<!DOCTYPE composition PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
template="#{theme.template}">

<ui:define name="content">
<div class="blogEntry">
<h:form>
<div>
<h:outputLabel for="password">Password:</h:outputLabel>
</div>
<div>
<h:inputSecret id="password"
value="#{identity.password}"
size="15"
maxlength="15"/>
<h:commandButton value="Login"/>
<h:commandLink styleClass="languageSelectorLink" value="EN" action="#{localeSelector.selectLanguage('en')}"/>
<span class="errors"><h:message for="password"/></span>
<span class="errors"><h:messages globalOnly="true"/></span>
</div>
</h:form>
</div>
</ui:define>

</ui:composition>

Please see uploaded files.

IDEA adds Seam specific variables on presence of 'xmlns:ui="http://java.sun.com/jsf/facelets"' in root tag. Do you have such declaration?

Yes, all jspx files have such declaration.

The really strange part of this issue, is that IDEA resolves some of the methods but not all of them.

this observation completely changes the problem (if only certain methods are not resolved):
actually IDEA shows methods that have signature as specified in attribute definition e.g.
'action' attribute (e.g. in ) should have method signature 'java.lang.Object action()' and logout method in identity has void return type

Do you have enough information to solve the problem (if possible) or do you need more information?

I would really appreciate particular method names that are not resolved (except logout :)

At the moment I can't :-( because I don't have an overview of all the 'missing' method names.
And also some of my own (custom) Seam components are not resolved 100%.

'localeSelector' suggestions box is empty but it looks like it's resolved in some way, because some of the methods is
not flagged as error in the editor - see jetbrains-example-localeselector-suggestions.jpg

Would it be possible to scan all sourcefiles (background task - or when you edit a file) with a @name annotation and include all public methods in the IDEA 'Seam suggestions library'?