Placeholder content not visible in Preview

I am a RoboHelp10 newbie with two projects on the go, one inherited and one new.  Placeholder content (breadcrumbs and Topic TOCs) is visible in Preview mode (Ctrl+W) in the inherited project, but not in the new project.  They don't show in Firefox/IE Preview either.  All other content/formatting seems to preview just fine.  MS_HTML_Help is the designated primary layout for both projects.  Based on a post in this forum, I tried updating DHTML effects, but it didn't help.  Any suggestions?

I am assuming if they don't appear in Preview, they won't appear in the generated CHM.  Correct?

RESOLUTION:  I finally fixed the problem with brut force by starting a new project and importing the HTML pages, etc.  Even then, it took a few tries before it worked.  Still don't know the underlying cause. 

Message was edited by: Steve@SSA on 16Nov2013