I don't think so. The TABINDEX attribute is a basic HTML property. JSF will render it when it is coded, and all popular browsers - including Mozilla and Firefox - will honor it. And, in fact, have honored it since the dinosaurs were using the web.
Of course, there is one caveat. TABINDEX only works for input controls that are defined as tabbable. That includes things like inputText, selectOneMenu, checkboxes, radio buttons, and so forth. When in doubt, check the JavaDocs. And, of course, remember that JSF is case-sensitive, unlike HTML.
An IDE is no substitute for an Intelligent Developer.