diff --git a/editor/libeditor/base/Makefile.in b/editor/libeditor/base/Makefile.in
index 756fa2ce4a6..81c5bdc964b 100644
--- a/editor/libeditor/base/Makefile.in
+++ b/editor/libeditor/base/Makefile.in
@@ -92,4 +92,5 @@ include $(topsrcdir)/config/rules.mk
 INCLUDES	+= \
 		-I$(topsrcdir)/content/base/src \
 		-I$(topsrcdir)/content/events/src \
+		-I$(topsrcdir)/layout/style \
 		$(NULL)
diff --git a/editor/libeditor/base/nsEditor.cpp b/editor/libeditor/base/nsEditor.cpp
index a09c794c476..2cfab8a8bd2 100644
--- a/editor/libeditor/base/nsEditor.cpp
+++ b/editor/libeditor/base/nsEditor.cpp
@@ -110,6 +110,7 @@
 #include "nsIParserService.h"
 
 #include "nsITransferable.h"
+#include "nsComputedDOMStyle.h"
 
 #include "mozilla/FunctionTimer.h"
 
@@ -3971,11 +3972,15 @@ nsEditor::IsPreformatted(nsIDOMNode *aNode, PRBool *aResult)
   
   nsCOMPtr<nsIPresShell> ps = do_QueryReferent(mPresShellWeak);
   if (!ps) return NS_ERROR_NOT_INITIALIZED;
-  
-  nsIFrame *frame = content->GetPrimaryFrame();
 
-  NS_ASSERTION(frame, "no frame, see bug #188946");
-  if (!frame)
+  nsRefPtr<nsStyleContext> elementStyle;
+  if (content->IsElement()) {
+    elementStyle = nsComputedDOMStyle::GetStyleContextForElement(content->AsElement(),
+                                                                 nsnull,
+                                                                 ps);
+  }
+
+  if (!elementStyle)
   {
     // Consider nodes without a style context to be NOT preformatted:
     // For instance, this is true of JS tags inside the body (which show
@@ -3984,7 +3989,7 @@ nsEditor::IsPreformatted(nsIDOMNode *aNode, PRBool *aResult)
     return NS_OK;
   }
 
-  const nsStyleText* styleText = frame->GetStyleText();
+  const nsStyleText* styleText = elementStyle->GetStyleText();
 
   *aResult = styleText->WhiteSpaceIsSignificant();
   return NS_OK;