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/elements/ExtendedItem.java
provider.setEncryptionHelper( propDefn, encryptionID );
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.core.DesignElement#hasLocalValue(org.eclipse.birt.report.model.metadata.ElementPropertyDefn)
	 */
	protected boolean hasLocalValue( ElementPropertyDefn propDefn )
	{
		if ( propDefn == null )
			return false;
		if ( !propDefn.isExtended( ) )
			return super.hasLocalValue( propDefn );
		return provider.getExtensionProperty( propDefn.getName( ) ) != null;
	}
	/**
	 * Checks the compatibilities for this extended item.
	 * 
	 * @param module
	 * @return
	 */
	public StatusInfo checkCompatibility( Module module )
	{
		// check this element itself
		StatusInfo status = doCheck( module );
		List errors = new ArrayList( );
		boolean hasCompatibilities = false;
		if ( status != null )
		{
			errors.addAll( status.getErrors( ) );