Style sheet files should be created and maintained with the Style Sheet Editor. This tool covers style sheet manipulation on a very low level. Maintaining style sheets with the Style Sheet Editor means that all information that you enter is kept separate from the style sheet itself.

From release to release, Application Designer adds new controls to its control library. As a consequence, the style sheet template is typically enhanced with every new control. When you work with the Style Sheet Editor, this is done automatically. You just have to regenerate your own style sheet file.

Otherwise (if you have manually created your own style sheet file), you always have to have to embed the enhancements into your style sheet file when Application Designer does style sheet changes: you have to copy the additional Application Designer style classes from the standard Application Designer style sheet file (CIS_DEFAULT.css) into your own style sheet file. Use a diff-viewer/diff-editor to do this.