Theme Editor Introduction
The following is an image of the Themes Editor (the screen shows a hierarchical structure of nodes):
It can be observed going down the hierarchical structure, that there is a "Classes" node and a "HTML Nodes" node (left part). In the center, we have the properties corresponding to each one of the Classes and HTML Nodes; and to the right, a preview, which is a view of how a control associated to the corresponding class will be viewed in runtime.
Generally, the Classes Node consists of all the predefined GeneXus classes, which can derive new classes and be associated to GeneXus controls.
The HTML Nodes consist of different CSS selectors and their combinations, which are not necessarily classes, but other selectors (as HTML Tags and custom classes) which cannot be associated to GeneXus controls.