XUI editor is a simulation editor for the executable UI in runtime, such as Dojo pages. The widget styles for the XUI editor and runtime pages are different. This difference is caused by the technologies that support the different styles. The widget style in XUI editor is based on eclipse SWT and draw2d technology, so the style design is from operating system. However, the executable runtime style is from CSS. To solve this problem, UDTT provides a mechanism to apply runtime CSS to XUI editor. Technical developers can also extend the mechanism by using the extension point. See CSS Support for XUI Editor Extension for more details.