Drop Down List functionailty changes with EHP4 / NW EP1

Since applying ERP Enhancement Pack 4 and NW EP1 we are having a number of issues with the rendering of our Web Dynpro ABAP Applications. The main problem that users are complaining about is the drop down functionality. Previously users could tab into a drop down list and start typing and the list would display starting at the letter they had first typed in. This no longer happens. You have to have either mouse clicked into the field and then start typing or you can tab and press f4 and then start typing. The users are finding this very annoying. Does anyone know how this can be fixed or do we just have to live with it now??

Thanks in advance.