Clarification about different forward voltage leds in series

DVDdoug:
A power supply cannot really "control" both current and voltage (because of Ohm's Law).

It's not uncommon for a power supply to have a current-limiting circuit. ...

The OP is referring to a device intended to be used to drive high power LEDs ["mean well driver "]. It provides both voltage regulation and current regulation. Thus it controls the current up to the set voltage, and then it voltage regulates.