After selecting a layer, click again for a pop-up layer menu panel.
Click to duplicate the current layer.
Click to merge the current layer and the one below.
Click to merge all layers.
Click to clear the current layer.
Click to lock the transparent pixels of the current layer so that you can only paint in pixels that are opaque.
Click to delete the current layer, which can be retrieved by undoing the operation.
Click to create a new layer mask for the current layer.
Drag the slider to adjust the opacity value of the current layer.
Select to blend the current layer and the one below, you can choose among 24 blending modes.