Version 0.4.7.3 .

editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/internal/analysis/model/ProjectManagerImpl.java

Index: editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/internal/analysis/model/ProjectManagerImpl.java
===================================================================
--- editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/internal/analysis/model/ProjectManagerImpl.java	(revision 21601)
+++ editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/internal/analysis/model/ProjectManagerImpl.java	(working copy)
@@ -140,15 +140,20 @@
 
   @Override
   public AnalysisContext getContext(IResource resource) {
+    if (resource == null) {
+      return null;
+    }
     return getProject(resource.getProject()).getContext(resource);
   }
 
   @Override
   public IResource getHtmlFileForLibrary(Source source) {
     AnalysisContext context = getContext(getResource(source));
-    Source[] htmlSource = context.getHtmlFilesReferencing(source);
-    if (htmlSource.length > 0) {
-      return getResource(htmlSource[0]);
+    if (context != null) {
+      Source[] htmlSource = context.getHtmlFilesReferencing(source);
+      if (htmlSource.length > 0) {
+        return getResource(htmlSource[0]);
+      }
     }
     return null;
   }