BTW, on the PC it's Ctrl-E for "Merge Layers" and Shift-Ctrl-E for "Merge Visible".

Hoofdcommissaris? I'm curious .. Why would you create a new layer atop the layers if you were going to merge them anyways? If you really wanted merged layers then you just merge them without creating a new layer.

RAWeaver's method was to "maintain the integrity of your originals" since the question was "a way of doing this without merging my layers".