# Candera System

#### Property Validation

A new macro CdaValidityTest allows the definition of a validation function for [Widget](http://dev.doc.cgistudio.at/APILINK/class_candera_1_1_widget.html "Abstract class for Candera Widgets."), [Effect2D](http://dev.doc.cgistudio.at/APILINK/class_candera_1_1_effect2_d.html "Base class for all 2D effects which can be added to a 2D RenderNode.") and Gdu properties. In case of failed validation the property will be highlighted in SceneComposer property list and an error message will be displayed.

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