You're welcome.
As a temporary "fix" you might like to think about adding sample text - in a language you don't normally use, so it stands out - to text frames when they're created. That way they don't get "lost". (The amount of times I've been distracted and then had to hunt around for an invisible frame I couldn't say. I'm easily distracted.)
If you do this, you might also try changing your default style to something "horrible" - e.g. bright red Comic Sans 30pt, or whatever - so it's easy to see where your "unused" frames are. You can then change the style to a "proper" one when you come to edit the frame. (It's worth noting that the font in the default style is automatically added to any PDF that is generated with embedded fonts. This may or may not be an issue however.)
On a more general, but related note, I think it would be great if Scribus had a "find empty frames" feature for document clean-up purposes, and others have asked about it on the forum, but whether it becomes a feature in the future I couldn't say. Maybe if the Outliner gets a makeover at some point?