原來是有隱藏密技
http://www.novell.com/documentation/ope ... _desk.html Using Different Options for Each Virtual DesktopThough somewhat more complicated than with KDE 3.x, you can configure your virtual desktops in a way that allows you to use different wallpapers or widgets on each.
NOTE: Combining Virtual Desktops with Plasma Activities
Note that the implementation in this release of KDE is still in an experimental state. Some features may not work as expected.
To access the relevant configuration options, you need to show the cashew icon at the upper right corner first (in openSUSE it is not visible by default). To do so, right-click an empty patch on your desktop and select Desktop Settings. In the dialog that appears, click
Type below Desktop Activity and select the Desktop - Default Desktop Containment entry from the list. Click OK to confirm the settings and to close the dialog. Now the cashew icon is visible at the upper right corner of your desktop.
1. Click the cashew icon at the upper right corner of your desktop and select Configure Plasma.
2. In the Plasma configuration dialog, activate Different Activity for Each Desktop and click OK.
From now on, each of your virtual desktops will have separate plasma activities. This will allow you to have a different wallpaper on each virtual desktop, as well as a completely separate set of widgets.
3. Now switch to the virtual desktop you want to configure and set a custom background as described in Changing the Desktop Background or add new widgets for the virtual desktop as described in Adding Widgets to the Desktop.
To make all virtual desktops appear the same again and to remove the binding between virtual desktops and activities, zoom out of your current desktop again and deactivate Different Activity for Each Desktop in the Plasma configuration dialog.