Sorry to burst your bubble but this isn't happiness about more room but rather
abnormal, non-adaptive behavior, a form of Stereotypy, or even OCD.
You can observe it also on the Chelmon and the Lo. They all act unnatural.
Those fish should rather constantly scout the rockwork for their next bite, but that rockwork is way too minimalistic to meet their needs. Regals primarily need caves and overhangs, not just open swim room.
As a rule of thumb, every time you see a fish for a long period of time swim in monotonous repeating pattern - especially along the glass - the fish doesn't feel at home in the tank.
It may be OK when the fish was just placed into the tank and hasn't yet settled in, but you shouldn't see it in an established fish.