@struso
The Roku streaming players have no HDMI input capability. They are just like your DVD player and the Google TV dongle - they are just another HDMI device. You will need to change HDMI Inputs through your Magnavox TV (using the Magnavox TV remote).
A RokuTV is a TV with an integrated Roku OS, rather than attached via HDMI like a Roku streaming player. The ability to show these Inputs on the Roku Home Screen are due to the integration of the Roku OS with the actual TV hardware.
Roku Community Streaming Expert
Just another Roku user... I am not a Roku employee.
Insignia RokuTV, Ultra 4660, Premiere+ 3921, Express 4k+ 3941, Streambar 9102