[KevinH]

Again, something is different as all of my tests show the new force_titlecase replace function works as I posted it, against all your tests on both macOS and linux machines I have to test with.

Please show a screencap of the python function editor showing your version of the force_titlecase function, and a screencap showing it being used in Sigil's find and replace.

If they are identical then something is broken somewhere in your setup. The replace_titlecase does work with all lowercase strings and we are making them lowercase in the force_titlecase replace function I posted by invoking replace_lowercase first.

Maybe some indentations in the python code got changed someplace?

It is very strange you are not seeing what I am seeing when adding and using the force_titlecase replacement function.

Something is different but I do not know what. The unchanged titlecase.py function does work when given mixed case or all lowercase test. We proved that earlier.