Anemone on the move

I went out the other day for a little post-thanksgiving shopping & when I returned home I was greeted with a big surprise. After over 4 months of happiness living in the same spot on the reef, my bubble tip anemone (E. quadricolor, at left) decided to move to the lower left corner of the tank. The first thing that ran through my mind was "uh-oh, whats wrong?" but then after a water test (everything was spot-on), a feeding, and a few days of observation... everything seems ok. The anemone isn't bouncing around, the clown fish which used to host inside the anemone is still hosting despite the new neighborhood, and save for some mushroom corallimorphs who don't welcome the competition, all of the other critters seem generally unaffected by the move.
All I can do now is sit back and watch. I kind of wish he'd move back... I now have a huge hole in the center of my tank where the anemone used to live and I'm not about to put anything else in its place... oh well, I guess I should give him the freedom to at least move around since he no longer calls the vast ocean his home. Below is a photo that documents the move.