"Save as" autofill not working

Mouse works reliably. Just tested it in the other views... works in list and column view but not icon view!

Thanks for your suggestion, however the question is not about how to save, or how to duplicate a file... I am able to save and name files without issue. The problem is, I used to be able to click on any existing files title to autofill the "save as" dialogue box. Then I could overwrite or rename my new save from there. Currently if I click on an existing file, the save as dialogue box remains empty or as "untitled". Furthermore, it is not an issue with Pages alone. Any application that opens and saves any kind of file has this same limitation.

In the image example below; I used to be able to click on "Artist Bio", "Artist Statement", "Artist Resume", etc. Then that name would appear in the "Save as" box and I could edit it from there before saving. Currently, clicking any of those does nothing, and the save as box remains unchanged.

It is most problematic when I have a long file title, and I wish to save another file with the same title, but change a character or two. I have to re-type the whole thing, instead of just clicking an existing file.

Thanks again for your suggestion.

Thank you for your reply. Yes, I know it's supposed to work, but it doesn't on mine. When I click an existing file, nothing changes in the save as box. Is it possible this is an option in some settings menu that can be toggled off/on? Again, it is any app, not just pages or numbers etc.