Why the preview of layers disappear?
Hi again,
I have this question but I don't remember if it was solved yet.
In my current workflow, I see this:
(the preview of the layers don't show up anymore). Do you know why, or if is a bug?

Detail:

It's since I use Photoshop elements that happens this. At the beginning, I can see the preview of each layer, but after a while when I working, or make some 'merge', the preview disappear.
Thanks again for the help in advance!
