Hi, I may not be on the right place to report this, but I don't know how to report the problem I encounter.
I installed Krita 4.0 from ppa deposit on kubuntu 17.10. And since then I'm not able to use the inherit alpha feature in new documents. What I do : just click on the "alpha" sign next to the layer in the layer docker. The sign is then highlighted as it used to in Krita 3. But nothing else happens and the layer content is not clipped.

I tested the feature on my old .kra files created before with Krita 3...inherit alpha works perfectly on former layers and I can create new layers and apply inherit alpha on it.

So before calling it a bug, I'd like to know if I'm missing something in the way I create new documents ?

PS : However I noted that the destructive way to do clipping (i.e. preserve alpha button) works fine.

Krita 4.0.0 on Linux, inherit alpha, works fine for me so I hope you don't mind me asking you this:

When you created a new document in krita 4.0.0, did you remember to delete the solid white Layer1 before trying to use inherit alpha on higher layers? (I often make that mistake.)
Or, you can group the layers of interest since inherit alpha only works within a group (unless alpha passthrough is used).

You are right, that was exactly what happened : I did not try to group the layers ans Layer1 was there. Then I realize that it was surely a bug in Krita 3 because I could use inherit alpha between 2 layers without grouping them (and with a 100% opacity filled layer underneath). So for very simple artworks with only a very few layers I did not bother to group layers.

But it doesn't matter now, Krita 4 is great - and not bugged for that matter. Thanks a lot !