hi, just got my first mac (long time windows user) apple support says that a few simple things dont work like they do on windows pc. 1. i connect my imac with my tv via hdmi. i start a movie and move it to the tv and select full screen. now i want the imac to go completely black. (dimming the display doesnt make i completely black) windows does this automaticly 2. with windows i can have my tv always connected to the pc and select where i want to output the picture. only the main monitor - only the external tv, or both with mac i have to disconnect the cable from the mac, otherwise it always shows me the external tv in the system settings (although its not even on) and when i move with my mouse and windows they disappear into nothing. i know there is the sync screen option, but after a restart of the mac it always takes the lower resolution of the 1080p tv and uses this for the 5k imac anyone know something that could help me?