Version: (using Devel) Compiler: GCC 4.3.2 OS: Linux Installed from: Compiled sources Using KDE 4.1.87 when I log in into laptop with external screen plugged in plasma is confused, puts panel on smaller desktop or doesn't put it at all. I have to kill plasma, remove it's configuration use xrandr to enable only external monitor and start plasma again. Initial mode is xorg default - smaller laptop screen displaying part of bigger screen, it was working with 4.1 series - external monitor was primary.
the only thing that's really changed here is the introduction of kephal. passing it on in that direction to see what they can make of it. you will probably need to provide more information on your x.org configuration for them.
*** This bug has been confirmed by popular vote. ***
For me plasma works, regarding to this problem, very flawlessly. The main problem might be, which of your displays is set as the "Default" or "Primary" display. I think i have the same setup as you. I use a notebook for my business work and now and then i am connected to an external monitor. When my Notebook is docked, my primary display is set to the external (bigger) monitor. So my panel and all plasmoids are displayed on this device. If i undock, the panel is displayed on the internal display build into my notebook. So in undocked state the build in display is set to primray. In docked state the external monitor is set to primary. If you have an nvidia card you might take a look at disper: For docked state, big screen left of notebook: disper -r auto -d DFP-1,DFP-0 -t right -e As you see DFP-1, my external monitor, is set as primary display.
I find plasma working quite well with multiple screens in KDE 4.4. Closing as worksforme. If you still have issues, reopen, or better, make a precise bug report what goes wrong.