Modify the DerivedAnnotationValueProvider (org.fortiss.tooling.base.ui), such...

Modify the DerivedAnnotationValueProvider (org.fortiss.tooling.base.ui), such that the editability of the annotation editing support mirrors the behavior of the derived annotation.

org.fortiss.tooling.base.ui/trunk/src/org/fortiss/tooling/base/ui/annotation/valueprovider/DerivedAnnotationValueProviderBase.java

@@ -124,7 +124,12 @@ public abstract class DerivedAnnotationValueProviderBase<T extends IDerivedAnnot
 	/** {@inheritDoc} */
 	@Override
 	public boolean canEdit(T specification, String instanceKey) {
-		if(isDerivedKey(instanceKey) && !isEditableByUser) {
+		if(isDerivedKey(instanceKey) &&
+				!isEditableByUser ||
+				(isEditableByUser && (!specification.isUserAnnotatedValuePreferred() && specification
+						.getDerivedValue() != null))) {
+			// Deactivate editing if the editing is principally disabled or the derived value would
+			// override the user annotated one.
 			return false;
 		}
 		return super.canEdit(specification, instanceKey);