It is commmon for new clown arrivals to hang out near a top corner, but 2 weeks seems a little long. I dont think its seeing a reflection. A fish looking out through a single pane of glass is not getting a reflection.. just like when you look in through a single pane, you dont see a reflection. (stick your head in and give it a try (J/K)
When you look through the front and try to see out the side, the two pains of glass at a 90 degree angle are causing the refraction which creates the reflection.
Are there any other fish that are pestering the clown?
are there any places for the clown to hide in/host in/call home?