Strange TV, Blu-Ray Remote Conflict -- HDMI switchbox to blame?

I have an odd problem with the remote control for my Panasonic BD30 Blu-ray player, located in my living room, suddenly turning on the Vizio VA320M TV, located in my adjacent dining room, wherever I press the "Play" button on the Panasonic. So I'll go into the dining room and turn off the Vizio TV -- but turning off the Vizio (whether by its remote control or at the set itself) will then turn off the Panasonic blu-ray player. That means I can't watch my blu-ray player (which is feeding a large Mitsubitshi TV in my living room), unless I don't mind the Vizio TV in the next room being on at the same time, with no one watching it (or I unplug the Vizio TV from the wall so it can't turn on.)

I thought this was strange enough, but then I discovered that the problem seems to be related somehow to a 4 x 2 HDMI Powered switch box (product 5312) purchased from monoprice. The switch box has one HDMI-out going to the Mitsubishi TV in the living room, and the other HDMI-out to the Vizio TV in dining room. I'm using three of its available four inputs for a Dish VIP 722, the Panasonic blu-ray player, and a Roku box. It all works quite nicely, and I'm pleased that I can watch any of my three video sources on either TV, or on both TVs at the same time. That is, I'm pleased -- except for the mysterious remote conflict. I believe the conflict must have something to do with the HDMI switch box, because when I disconnect the Panasonic blu-ray player from the box, pressing its play button no longer turns on the Vizio TV -- and turning off the Vizio no longer turns off the blu-ray player.

Has anyone ever heard of such a thing? Would replacing the blu-ray player with one from another manufacturer solve the problem? Is there any other technical solution?

(I can connect the blu-ray player to another HDMI input on the Mitsubishi, leaving only the Roku and the VIP722 connected to the switch box -- the Roku doesn't seem to conflict with anything. That at least lets me watch the blu-ray player on the Mitsubishi without turning on a TV in the next room, but it means I can't watch the blu-ray player on the Vizio.)

That sounded like an idea, so I just connected the HDMI-out from the blu-ray player to input #4 on the switchbox -- it had previously been connected to input #2 (VIP 722 is still on 1, Roku on 3). But the result is the same -- hitting the play button on the blu-ray player still turns on the Vizio TV, and turning off the Vizio TV still turns off the blu-ray player.

Thanks for the info. It turns out that CEC is indeed the issue, and that the Panasonic blu-ray player is turning on the Vizio via CEC though HDMI, and the Vizio is turning off the Panasonic. Unfortunately, there is no way to turn off or disable the CEC function on the Vizio TV, a fact that has now been confirmed for me by Vizio's tech support people. But luckily, Panasonic's brand of CEC, which is on by default in the blu-ray player, CAN be turned off in one of the menus. I just did that -- problem solved. It would be nice if Vizio (and all other manufacturers) made it possible to disable CEC, and better documented the function. But at least I learned something...