Page 1 of Sony TV`s & RGB

Just a minor question which I wonder if anyone knows the answer to. When I switch on my Toshiba DVD, which is set to output RGB, it `grabs` the Sony TV set I have, but doesn`t display the RGB `input`. Anyone familiar with sony`s will know on the handset there is a logo of a TV creen with an arrow pointing into it. This toggles around the AV functions, and the RGB is the second one on AV2. So the Tosh grabs the AV2 socket, but I still need to press the tv screen button in order to get an RGB display. Is this a common thing, or should the TV display it automatically?
Thanks for any help
Vince

all the sony tvs I have used have been like this but I daisychain the video player and reckoned that was the reason, might be wrong, but theres nothing wrong with your t.v.