The drag and drop concept could be important in order to track the
Deployment diagram elements
used in more than one diagram.
In a Deployment diagram, you can drag and drop both Java and UML
elements
from:
1. From the Package Explorer you can
drag and drop the following Java
elements:

2.
From the Model Editor you can
drag
and drop the following Java or UML (just
a metamodel element not related to Java) elements: