Two screens, separate desktops
I've got an Asus VS239H-P monitor connected via single-link DVI, typically. I use that for all the computer work. Connected with HDMI, typically, I also have the Samsung 5064 plasma tv, on which I occasionally view videos played from the computer. So, I want to configure them as separate desktops. The Asus monitor is, normally, the only one displaying what happens on the computer. One problem I've had is a program started on the monitor desktop will open on the plasma tv. As the tv is not normally set to display computer output, that won't work. I'll avoid mentioning other problems until or if they seem to be relevant.
For a long time, I used a variety of nVidia cards. For years, I struggled to get this configuration to work, with less than ideal results. Some months ago, I got a used HIS Radeon HD 6950 and was able to fairly easily set up what I wanted. That card died.
I've tried two different AMD cards after that and currently have an XFX Radeon HD 7850 installed. It's a challenging puzzle to try to overcome the conflicting effects of Catalyst Control Center and the Display module in KDE Systemsettings and I haven't succeeded with that combination. By copying a saved xorg.conf that worked for the 6950, it works, as long as I don't touch either of the configuration programs, so that is, almost, good enough.
A possibly related issue is OpenGL cannot be selected for the desktop effects compositing method. ISTR fixing this not too long ago with a simple flip of a configuration switch, somewhere, but I can't find any evidence to support that foggy memory. :p jclvanier has this working with an Intel graphics adapter, so I'm interested if this type of two-screen system works well for someone with Intel graphics. Any tips would be appreciated!