Bug 202121 setDateFormat does not working
If you want to set date format of the table column style you have to use setDateTimeFormatCategory and setDateTimeFormat instead of setDateFormatCategory and setDateFormat. If you will try to use setDateFormatCategory in the first case in xml-source you will see that your style contains dateFormat property. This property is not working at all, in the second case in xml-source you will see that your style contains dateTimeFormat property. I think it will be better if the result of setDateTimeFormatCategory and setDateFormatCategory will be the same.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/parser/EngineIRVisitor.java
* certain features that are not quite suitable for FPE use. In particular, this
 * step of the reconstruction is needed for several reasons:
 * <p>
 * <li>Style handling: DE stores all styles in an unflatten version. Factory
 * needs to reference styles where the element hierarchy has been flattened.
 * <li>Faster lookup: DE stores various properties as property name/value
 * pairs. Factory IR might store them as structure. See
 * <code>createHighlightRule()</code> for an example.
 * <li>Merging properties: DE stores custom and default properties separately.
 * In FPE, they are merged.</li>
 * <p>
 * 
 * This class visits the Design Engine's IR to create a new IR for FPE. It is
 * usually used in the "Design Adaptation" phase of report generation, which is
 * also the first step in report generation after DE loads the report in.
 * 
 * <p>
 * special consideration in styles
 * <p>
 * BIRT uses a simlar style mode with CSS, but not exactly the same. The main
 * differences are:
 * <li> text-decoration is not inheraible which simplify the CSS standard. This
 * rules makes text-decroation are usless for all the containers. As the HTML
 * treat the text-decoration inheritable in block-level element, the ENGINE must
 * remove the text-decoration from the container's styles.
 * <li> BIRT doesn't define the body style, it uses a predefined style "report"
 * as the default style.
 * 
 */
public class EngineIRVisitor extends DesignVisitor