Picture in the working field is NOT MASKED (render is ok)

[ManHeaven]

Hello everyone!
There is a weired problem.
I have a masked bone layer with a character's head (i apply "reveal all" to this layer). In the settings of the head's form layer i applyed masking - "clear the mask,then add this layer to it".

The problem is with the "mask this layer" option, when I use it with eyes. The result of masking appears only after render. The eyes are supposed to be hidden by mask beyound the form of the head and to be shown on the head.

The gist is: render shows the correct masked picture, but the program field doesn't show the result of masking.
Can you help to solve this problem?

In Display Quality masking is on. I use Anime Studio Pro 9.2
Program field

After render

[Maxwell]

i don't think this is a problem it's just how it goes because i got the same thing

[slowtiger]

Sometimes the preview doesn't show exactly what you want. As long as the render is OK, I don't mind.