Help links suddenly opening new window

This has never happened before, but all of a sudden, links are opening a new window. I haven't made any changes except to content in quite a while. What could cause that? We are getting ready to release and this happens! 

I am using RoboHelp 7, by the way.... and publishing to chums.  And our TOC is merged. We have 40 projects. We will change that soon, but it's what we have for this release....

Thanks!