Merge a layer downward in a notebook.

1. Open a notebook.  
2. Tab the button List Form in the top-right hand corner. 
3. Tab Layers. Locate the layer that you would like it to disappear while moving all its content down one layer. 
4.  Tab the button More on the far right. 
5. Tab Merge Down. That layer will be deleted, but its content is merged with the layer below it.