Summary
Some elements cannot be anonymous.
Details
In UML, elements of the following metaclasses must always have a name:
- 
AnalystProject
 - 
Artifact
 - 
Attribute
 - 
AttributeLink
 - 
Class
 - 
Collaboration
 - 
CollaborationUse
 - 
Component
 - 
DataType
 - 
Dictionary
 - 
Enumeration
 - 
EnumerationLiteral
 - 
EnumeratedPropertyType
 - 
Event
 - 
Interface
 - 
Link
 - 
Node
 - 
NoteType
 - 
Operation
 - 
Package
 - 
Parameter
 - 
Project
 - 
Property
 - 
PropertyEnumerationLitteral
 - 
PropertySet
 - 
PropertyType
 - 
Requirement
 - 
RequirementContainer
 - 
Signal
 - 
StateMachine
 - 
Stereotype
 - 
TagType
 - 
Term
 - 
ActivityDiagram
 - 
BpmnProcessCollaborationDiagram
 - 
BpmnSubProcessDiagram
 - 
CommunicationDiagram
 - 
SequenceDiagram
 - 
StateMachineDiagram
 - 
ClassDiagram
 - 
DeploymentDiagram
 - 
ObjectDiagram
 - 
UseCaseDiagram
 
Tips
Edit the name property of the element.