XPFE XPToolkit
XPFE & XPToolkit permit consistent creation of user interfaces across the 3 major platforms. As for why the two names: "'XPToolkit' is rather synonymous with XPFE. Though the former term seems more concrete than the other, and therefore is not an exact replacement, no one is completely certain why we have both." [1]. From here on in we'll refer to XPFE (because it's shorter to type). Note: This is also commonly refered to as Toolkit.
XPFE uses XUL, XBL, and RDF to achive the goal of being able to programmatlically instantiate a button (for example) using the same api no matter what platfrom you are on. XPFE uses a combination native and custom widgets to achieve the toolkit. However, from the api perspective it is platform neutral.
