Having trouble changing Chapter Names in mkvtoolnix 57.0.0

I can’t seem to update to the latest model of MKVToolnix, so for now I’m stuck with 57.0.0.

Anyway, I’ve been making edits to a file’s tracks and Title in the multiplexer tab. There wasn’t an option to edit chapter titles in that tab so I had to reupload the same file into the chapter tab. There I could change the chapter names.

However, upon two attempts, the new version of the file retained the old chapter names.

Can someone please explain how I can change the chapter titles for the finished new version of the file?