This idea is aimed to add a little extra to the layers dialog.
I'm a guy that has come very used to paint with just 5 layers (not counting the Background Layer) and I find myself creating layers repeatedly when I merge layers together.
I would like Sketchbook to has this "feature" that when the user merges a layer, Sketchbook automatically creates a transparent layer in the same place where the merged layer was.
This should be an option, and the user should decided wether to set this Layer Behavior off or on.
This behaviour should be limited to a certian number of layers (for instance 5) because regardless of how many layers the user has, when they gets merged they'll always be replaced automatically.
If the behaviour is turned ON, then the max number of layers should be set to 5 (or set by the user under the preferences settings)
If the behaviour is turned OFF, then the layers should behave normally.
