CHM Window will refuses to display the correct Caption

I have RoboHelp 9 Help projects, that will only display the caption "HTML Help" regardless of what I enter in the Window configuration screen.

I have tried deleting all existing Wndows and then compiled the help without any window being defined. When opened, the chm displays in the top-right with a default caption of "HTML Help". I then created a new window, called it FRED, entered the string BILL in the Window Caption field (the caption display read correctly in the preview window). All other settings were left at the defaults. When I compile the help, still the default caption "HTML Help" displays.

I created a new, blank HTML project and gave it a custom Caption, again only the default caption will display.

If however, I amend the caption of an existing project, where the caption displayed is as defined in the Window Properties screen, the new chm displays the amended caption. I have compared all the settings in both Window configuration screens and they appear to be identical.

This problem has existed for some time, going back several versions of RoboHelp (to before I joined the company) but I didn't expect to see it in a new project created using RH9 HTML with all the latest updates.

Any ideas?

Thanks