Reply To: Adding a new Shapekey to “Piero” instantly moves Vertices

I still have a “Subsurf Modifier” in place. Should I apply it or could this cause problems with the “Shapekeys”? For the finetuning of the “Face Shapekeys” it would be good to have more geometry to work on but due to the bad experiences with “Shapekeys”, I’m still hesitating to apply the “Subsurf Modifier”: