Masks
Just in case you didn't know, a mask allows us to hide a certain area of the layer it belongs to. Although Photoshop Elements naturally supports only adjustment layer masks, its undocumented features let as mask any layer.
A single layer may contain up to masks - a pixel mask (often referred as "layer mask"), a vector mask, and a filter mask (applies only to smart-filtered smart objects).
To access the masking commands, you open the "Masks" dialog by double-clicking its thumbnail in the Effects palette.
The Commands list is sorted out according to nature of the mask and kind of the task. For example, on the screenshot you can see 3 command sets - for creating a new (pixel) layer mask, for handling the existing vector mask, and for adding a vector mask to the backward (below) layer.
 |
 |
