Hi everyone. I have 2 hd121hd headrest monitor. While fidling with the remote faced on one of the two monitors, i suddenly noticed that on the other one a hidden menu came out. In pressed something on the remote. Because when i saw the menu to choose the input source i noticed that usb and the hdmi input was gone on that list. Can somebody tell me how to go to that hidded/secret menu?i think its like a config menu in which there were a lot listed and one of those can hide or disable if want to disable the selection of that input source.thanks everyone.btw how can i post at the tech support topic?