. AMD Graphics Card - AMD RX 580X
With my old AMD GPU and CCC I could set up multiple configuration profiles of the 2 displays so that it was monitor 1 only, or monitor 2 only, or monitor 1 & 2 extended desktop. The profiles were then accessed via the CCC system tray icon. I used this when temporarily connecting a laptop to one or other of the monitors so that the desktop was using one monitor & the laptop used the other. Normal configuration is extended desktop.
With my new GPU came the crimson software which no longer seems to have this function. If I try to use eyefinity the displays disappear completely plus I don't think eyefinity was designed for this purpose. My only workaround at the moment seems to be to change the desktop via windows control panel each time which is a PITA.
You might not like this answer Mike... but with win10 and the same vidcard I can configure my 3 monitors any way I want and switch from one config to another.. easily.
You're right, that's not what eyefinity is meant to do.
I skipped over win7 so I really don't know what your options are but this win10 method is really simple.
1) choose "project" from notifications.
2) choose either PC screen only, extend, duplicate or second screen only.
If you need to change your default screen that's available too in display settings (right click desktop)
I'll admit I liked the old days where you could use key combinations to invoke monitor arrangements but I find this win10 method acceptable.