Cannot use TAB key after EHP2 at logon screen in IE9

Sincere,

Since we've implemented EHP2 on our CRM landscape, we miss functionality of switching fields at logon screen. Switching between Username and Password fields is not possible anymore, cursor immediately goes from Username to Language field. Note that this happens only in Internet Explorer 9, in Mozilla Firefox everything works fine (alternative check). Any clues, how and where to check for order of focus?

Also, could anyone provide any usefull data about how to set Internet Explorer 9 for best behaviour of SAP CRM?

Thank you in advance,

Matt