People, this has already been solved ... go configuration> advanced and in user interface, activate "Enable the Chromecast help center" ...
Once activated ... they write in the address bar - "opera: // cast" - and there they configure the Google Cast devices ...
Then, on a page like youtube, they click right and they transmit and they activate the transmit icon, and they choose the device ...
To make it easier to transmit later, I can right click on the icon and they will place "Show icon always"