I think what @Deckon27 means is that you can't use the arrow keys to move through merge modes on Mac like you can on Windows. This is simply because on macOS the drop-down input control isn't as keyboard-friendly.
However, for this reason I added the Shift+Alt+Page Up/Down shortcuts: use these to move through the merge modes for the active layer.
More layer shortcuts here:
http://www.ultrafractal.com/help/keyboard/fractalproperties.html
(The merge mode shortcuts are not listed here because they only apply to the Mac version and the online help is still for the Windows version. I plan to address that soon.)
I think what @Deckon27 means is that you can't use the arrow keys to move through merge modes on Mac like you can on Windows. This is simply because on macOS the drop-down input control isn't as keyboard-friendly.
However, for this reason I added the Shift+Alt+Page Up/Down shortcuts: use these to move through the merge modes for the active layer.
More layer shortcuts here:
http://www.ultrafractal.com/help/keyboard/fractalproperties.html
(The merge mode shortcuts are not listed here because they only apply to the Mac version and the online help is still for the Windows version. I plan to address that soon.)