diff --git a/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp b/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp
index 0590b6a..43615ae 100644
--- a/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp
+++ b/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp
@@ -213,6 +213,58 @@
   }
 }
 
+bool IsPageResourceShared(CPDF_Document* doc,
+                          RetainPtr<const CPDF_Dictionary> page_dict,
+                          RetainPtr<const CPDF_Dictionary> resources_dict) {
+  CHECK(doc);
+  CHECK(page_dict);
+  CHECK(resources_dict);
+
+  const uint32_t resources_object_number = resources_dict->GetObjNum();
+  if (resources_object_number) {
+    // If `resources_dict` is not an inline object, then check to see if is a
+    // shared object.
+    if (pdfium::Contains(GetObjectsWithMultipleReferences(doc),
+                         resources_object_number)) {
+      return true;
+    }
+  }
+
+  // The check above may not catch all cases. e.g. inline objects. Check all
+  // pages in the document to see if another page is using the same resources.
+  int page_dict_seen = 0;
+  int resources_dict_seen = 0;
+  for (int i = 0; i < doc->GetPageCount(); ++i) {
+    RetainPtr<CPDF_Dictionary> current_page_dict =
+        doc->GetMutablePageDictionary(i);
+    if (!current_page_dict) {
+      continue;
+    }
+
+    // Check to see if the current page's page dictionary is seen twice: Once
+    // for this page, and once for another. If the same page dictionary is in
+    // use twice, then the resource dictionary within must also be shared.
+    if (current_page_dict == page_dict) {
+      ++page_dict_seen;
+      if (page_dict_seen == 2) {
+        return true;
+      }
+    }
+
+    // Similar check as above, for the current page's resource dictionary.
+    auto page =
+        pdfium::MakeRetain<CPDF_Page>(doc, std::move(current_page_dict));
+    if (resources_dict == page->GetMutableResources()) {
+      ++resources_dict_seen;
+      if (resources_dict_seen == 2) {
+        return true;
+      }
+    }
+  }
+
+  return false;
+}
+
 }  // namespace
 
 CPDF_PageContentGenerator::CPDF_PageContentGenerator(
@@ -379,19 +431,14 @@
     return;
   }
 
-  const uint32_t resources_object_number = resources->GetObjNum();
-  if (resources_object_number) {
-    // If `resources` is not an inline object, then do not modify it directly if
-    // it has multiple references.
-    if (pdfium::Contains(GetObjectsWithMultipleReferences(m_pDocument),
-                         resources_object_number)) {
-      resources = pdfium::WrapRetain(resources->Clone()->AsMutableDictionary());
-      const uint32_t clone_object_number =
-          m_pDocument->AddIndirectObject(resources);
-      m_pObjHolder->SetResources(resources);
-      m_pObjHolder->GetMutableDict()->SetNewFor<CPDF_Reference>(
-          pdfium::page_object::kResources, m_pDocument, clone_object_number);
-    }
+  // Do not modify shared resource dictionaries. Give this page its own copy.
+  if (IsPageResourceShared(m_pDocument, m_pObjHolder->GetDict(), resources)) {
+    resources = pdfium::WrapRetain(resources->Clone()->AsMutableDictionary());
+    const uint32_t clone_object_number =
+        m_pDocument->AddIndirectObject(resources);
+    m_pObjHolder->SetResources(resources);
+    m_pObjHolder->GetMutableDict()->SetNewFor<CPDF_Reference>(
+        pdfium::page_object::kResources, m_pDocument, clone_object_number);
   }
 
   ResourcesMap seen_resources;