Here are the steps that caused the bug to manifest:

1. Installed JBoss Tools into Eclipse from the update site
2. Restarted Eclipse. Jboss Tools noticed my existing web project and hooked up to it.
3. At this point I had correctly working JSF2 content assist in my XHTML files
4. Used Git to switch to a JSF1 branch and used the same Eclipse workspace to work on that (Refreshed the workspace after the switch, w/o restarting Eclipse)
5. Used Git again to switch back to JSF2 branch

At this point JBoss Tools no longer provided me with content assist for JSF2 tags. It kept giving suggestions for JSF1. Restarting Eclipse or cleaning the workspace had no effect.

In order to fix the problem I had to do the following:

1. Close Eclipse
2. Delete all org.jboss.tools.* directories from .metadata/.plugins
3. eclipse -clean

After that JBoss Tools provides proper JSF2 content assist again, so this looks like a caching bug.

My workspace is setup with:

• Eclipse Helios
• JBoss Tools 3.2.0.v20110215-1535-H41-GA

My JSF1 branch contains these libraries under WEB-INF/lib and included in project build path:

• myfaces-api-1.2.4.jar
• myfaces-impl-1.2.4.jar
• jsf-facelets-1.1.14.jar
• richfaces-api-3.2.2.GA.jar
• richfaces-impl-3.2.2.GA.jar
• richfaces-ui-3.2.2.GA.jar

For JSF2 branch, the libraries are:

• jsf-api-2.1.2.jar
• jsf-impl-2.1.2.jar
• richfaces-core-api-4.0.0.Final.jar
• richfaces-core-impl-4.0.0.Final.jar
• richfaces-components-api-4.0.0.Final.jar
• richfaces-components-ui-4.0.0.Final.jar