Custom layer icon when it is empty

Hi, a lot of times i save masks and paths as a layer mask in the group of the object. So you can easy drop the folder into a compo and move your masks and paths along with it. And if you transform the folder the masks get scaled along. Also usefull to keep a sharp backup of your mask when the mask you use has a feather.

It would be helpfull if a layer with no pixels (in the left icon) would have a different icon so you can easy identify it as a 'mask' layer with no visible pixels in the 'layer miniature' so to say.