I connected my AV receiver to my iMac via the Thunderbolt-to-hdmi adapter but I do not have any TV connected to the receiver, meaning no screen.
The whole purpose of this was for being able to use the lossless audio output, especially because Apple dropped the toslink in lastest iMac.
On the audio part everything works fine but the problem comes from the fact that iMac thinks that has a second display attached and this is messing with apps that do resize windows,... I can even endup with accidental movement of apps to the hidden display.
How can I prevent iMac from using the second display but still using the HDMI output?