Hi, I am not sure what do you mean by modifying this window, but MOC means something like Microsoft Office Compatibility... This feature was installed when you installed Compatibility pack with 2007 version. So if you want to save some document let say in Word 2003 as 2007 format, you can either open it in Word 2003 and use Save as and then chose apropriate format or you can make it quickly by using this option...
My suggestion is to keep it as it is, it't nothing against nothing