bug 109569, r=fabian, sr=hewitt, need to get ok button via document.documentElement.getButton("accept)"

suite/common/history/findHistory.js

@@ -41,7 +41,7 @@ var gSearchField;
 function Startup()
 {
   var bundle = document.getElementById("historyBundle");
-  gOKButton = document.getElementById("ok");
+  gOKButton = document.documentElement.getButton("accept");
   gOKButton.label = bundle.getString("search_button_label");
   gOKButton.disabled = true;
   gSearchField = document.getElementById("searchField");