Polish accented characters are included in many standard Windows fonts (Times New Roman, Arial, Courier, etc.) The font used by default in this box includes them to (łżźćńśęąłó). To access them you need to change the keyboard layout. If you're using Windows go to Control Panel > Regional and Language Options > Languages > Details and choose "Polish Programmers" as a keyboard layout. You may need to install this layout from the Windows Installation CD. Then you should be able to use Polish diacritics by holding the left Alt key + appropriate letters.