I'm registering a custom validator for the UML2 EPackage in
EValidator.Registry.INSTANCE in an early-start plugin.
When I attempt to register my validator in my earlyStartup() method,
EValidator.Registry.INSTANCE already contains an instance of
org.eclipse.uml2.uml.util.UMLValidator. In order not to disregard it, I
have created a composite validator [1] that invokes both the custom and
the existing validator. So far so good.
However, when I right-click inside the UML2Tools class diagram editor
and select "Validate", the previously registered composite validator in
EValidator.Registry.INSTANCE is replaced/overwritten with an instance of
org.eclipse.uml2.diagram.common.validation.UML2ToolsValidato r - and as
such my custom validator never gets invoked.