Bug 432068. Fix stupid assumption in listbox code. r+sr=roc

layout/xul/base/src/nsListBoxBodyFrame.cpp

@@ -1208,20 +1208,24 @@ nsListBoxBodyFrame::GetNextItemBox(nsIBox* aBox, PRInt32 aOffset,
       // There is a content node that wants a frame.
       nsIContent *nextContent = parentContent->GetChildAt(i + aOffset + 1);
 
-      // Either append the new frame, or insert it after the current frame
-      PRBool isAppend = result != mLinkupFrame && mRowsToPrepend <= 0;
-      nsIFrame* prevFrame = isAppend ? nsnull : aBox;
-      
       nsPresContext* presContext = PresContext();
-      nsCSSFrameConstructor* fc = presContext->PresShell()->FrameConstructor();
-      fc->CreateListBoxContent(presContext, this, prevFrame, nextContent,
-                               &result, isAppend, PR_FALSE, nsnull);
+      result = presContext->GetPresShell()->GetPrimaryFrameFor(nextContent);
 
-      if (result) {
-        if (aCreated)
-           *aCreated = PR_TRUE;
-      } else
-        return GetNextItemBox(aBox, ++aOffset, aCreated);
+      if (!result) {
+        // Either append the new frame, or insert it after the current frame
+        PRBool isAppend = result != mLinkupFrame && mRowsToPrepend <= 0;
+        nsIFrame* prevFrame = isAppend ? nsnull : aBox;
+      
+        nsCSSFrameConstructor* fc = presContext->PresShell()->FrameConstructor();
+        fc->CreateListBoxContent(presContext, this, prevFrame, nextContent,
+                                 &result, isAppend, PR_FALSE, nsnull);
+
+        if (result) {
+          if (aCreated)
+            *aCreated = PR_TRUE;
+        } else
+          return GetNextItemBox(aBox, ++aOffset, aCreated);
+      }
             
       mLinkupFrame = nsnull;
     }