According to mjudge's caret api checkin comments, I think this is the proper fix for the xmlterm bustage. a=leaf

extensions/xmlterm/base/mozXMLTerminal.cpp

@@ -725,8 +725,9 @@ NS_IMETHODIMP mozXMLTerminal::ShowCaret(void)
       nsCOMPtr<nsIDOMSelection> sel;
       if (NS_SUCCEEDED(selCon->GetSelection(nsISelectionController::SELECTION_NORMAL, getter_AddRefs(sel))) && sel)
       {
-        caret->SetCaretVisible(PR_TRUE, sel);
+        caret->SetCaretDOMSelection(sel);
-        caret->SetCaretReadOnly(PR_FALSE, sel);
+        caret->SetCaretVisible(PR_TRUE);
+        caret->SetCaretReadOnly(PR_FALSE);
       }
     }
   }