I bought an LCD arm for one of my monitors (Benq T701).  It works great and allows me to rotate the monitor sideways for portrait mode.  I love having it up off the desk and being able to swivel it around so other’s can view it.

I tried the same arm on my Sony SDM-HS95P monitor but due to the mount not being centered it won’t stay in the portrait position.  It swings back to landscape mode.

Does anyone know of an LCD arm that perhaps locks in the portrait mode so the monitor won’t swivel back to landscape mode?