Fix for navigation reginos for instance creations with import prefixes.

pkg/analysis_server/lib/src/domains/analysis/navigation_dart.dart

Index: pkg/analysis_server/lib/src/domains/analysis/navigation_dart.dart
diff --git a/pkg/analysis_server/lib/src/domains/analysis/navigation_dart.dart b/pkg/analysis_server/lib/src/domains/analysis/navigation_dart.dart
index 855330efd8ca5b8ff4b470d51634c4eb6d428685..20ed6aad6213ff5a8d9e577bc25112242a890e33 100644
--- a/pkg/analysis_server/lib/src/domains/analysis/navigation_dart.dart
+++ b/pkg/analysis_server/lib/src/domains/analysis/navigation_dart.dart
@@ -288,7 +288,16 @@ class _DartNavigationComputerVisitor extends RecursiveAstVisitor {
     }
     // add regions
     TypeName typeName = node.type;
-    computer._addRegionForNode(typeName.name, element);
+    // [prefix].ClassName
+    {
+      Identifier name = typeName.name;
+      Identifier className = name;
+      if (name is PrefixedIdentifier) {
+        name.prefix.accept(this);
+        className = name.identifier;
+      }
+      computer._addRegionForNode(className, element);
+    }
     // <TypeA, TypeB>
     TypeArgumentList typeArguments = typeName.typeArguments;
     if (typeArguments != null) {