Problem with rigging several objects

I have a problem with a model I’m rigging.

What I’m doing is creating a base layer for the character, no hair or clothes, then on top of that, I have the clothes and hair as separate objects. I think this is the best way to do what I’m doing, as I’m going to be making several character, so I could just switch hair and clothes.

The problem is rigging the hair, clothes aren’t a big problem, but the hair has this weird glitch where if I tilt the head backward, the hair goes through the head, the weight paints on both the head and the hair for the head-bone are exactly the same, so I don’t know what could be causing the problem.

Here’s a screen shot I took, just in case you don’t know what I’m talking about:

So how do I fix it?

could be a couple things

  1. make sure there is only one armature modifier
  2. make sure that “bone envelopes” is deselected

Problem still persists…

I used to have this problem, and that used to do the trick, but this one’s somehow different.

So… no one has a solution?

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