Bug 213680 [2.2.2]Chart script can not be cleaned completely.
Description: Reset script or delete all script does not work. build version: v20071221-0630 steps to reproduce: 1. New a report. 2. New a chart. 3. Enter some script for the chart and save the report. 4. Click the reset scirpt button or delete all script. 5. Save the report and switch to layout,then switch back to script page. Expected result: Script are cleaned. Actual result: Script are not cleaned. Note: If you delete part of the script, it works.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/metadata/ElementPropertyDefn.java
* @return The (localized) group name, or null if the property is not in a
	 *         group.
	 */
	public String getGroupName( )
	{
		if ( groupNameKey == null )
			return null;
		return ModelMessages.getMessage( groupNameKey );
	}
	/**
	 * Indicates if derived elements can inherit the value of this property.
	 * Most properties can inherit values from a parent element. A few system
	 * properties, such as the name or extends, can't be inherited.
	 * <p>
	 * Note: This attribute is used for both style property and non-style
	 * property with two different meanings.
	 * <ul>
	 * <li>For style property, it determines whether this property can be
	 * cascaded from container;
	 * <li>For non-style property, that means whether this property can be
	 * inherited from parent.
	 * </ul>
	 * We take it because of the fact style is not inheritable, and the
	 * following diagram:
	 * <p>
	 * <table border="1" cellpadding="2" cellspacing="2" style="border-collapse:
	 * collapse" bordercolor="#111111">
	 * <th width="20%"></th>
	 * <th width="40%">can inherit</th>
	 * <th width="40%">can cascade</th>