Nightly build fixed my problem -- slight delay initially to fill the cache, from then on, no pauses.
Typo in "jsf/plugins/org.jboss.tools.jsf.ui/src/org/jboss/tools/jsf/ui/messages.properties" where it said "Enabale" in ENABLE_JSF_CODE_COMPLETION_TEXT
(too small for a JIRA)