Custom parameter “capHeight” doesn’t work like before

I recently discovered the custom parameter “capHeight” as being quite useful to set a different distance between the letters and accents for upper- and lowercase with the same set of accents by using anchors.

In new files I can set up a value for the CP but it doesn’t show in the letters and the anchors don’t move to that value with cmd alt u, which it did before.
Opening old files in which the CP worked still have the line and anchors sitting on it but nothing happens when I change the value of the CP.

Did the CP before did something that it was not supposed to do or is this a bug?
Anyway, it was really helpful before!

I’m running 2.5.2 (1176).

How exactly did you set up the parameter?

Pretty much just like that.
I created the “capHeight” CP with the value of 755 and by setting the anchors with alt cmd U they placed themselves on that height value.

You have the capHeight parameter on the same value than the default parameter. The shouldn’t change anything.

What the … ?

I see that only now. I didn’t pay attention to that because I seriously don’t remember having changed those values since the actual cap height was established forever ago.
Tracing back older files the cap height is different in those files the parameter is activated.

May I ask what the purpose of the capHeight Custom parameter is?

Does it work in the opposite way than I thought I was using it?
Put in a value in the normal parameter to use it for Anchors for example but have the proper value in the meta data of the font?

The parameter is supposed to be used to have a different cap height for different scripts. So you could do something like cyrillic:743.