This problem is addressed in ArcGIS 8.1.2.
Dragging and dropping more than one service into ArcMap may not work properly.
The problem shows up differently, depending on the operating system on which ArcMap is run:
1. When dragging and dropping an image service and a feature service into ArcMap, only the feature service gets added.
2. When dragging and dropping two feature services into ArcMap, only the first feature service gets added.
3. When dragging and dropping two image services into ArcMap, ArcMap will crash.
When dragging and dropping two services into ArcMap, the No Drop mouse icon appears, and the services cannot be added to ArcMap.