Calling SetStyleAuto() on a UI element is translated to SetStyle("ClassName") where ClassName is the name of the UI element’s class. It then searches for the name in the xml file set in SetDefaultStyle(). If you subclass from Button for example and call the new class MyButton, calling SetStyleAuto() will search for “MyButton” in the default style. If you don’t have a style set for it you’ll get a white rectangle or box.
A solution is to either to call SetStyle("Button") to get the parent’s style, or to define a style called “MyButton” in the xml and customize it
Also, in the RegisterObject() method (if you made one) calling URHO3D_COPY_BASE_ATTRIBUTES(ParentClassName) after registering it is important to make sure the editor knows how to handle it.
EDIT: wtf I just want to talk about UI





