Bug 151552 Can't change the Data Set of a chart drag from a library
After creating a library with a chart,you use it and drag the chart to a report design.A error happen when you change the Data Set of the chart. 1.creat a library,add a chart into it ,then publish the library. 2.new a report and use the library ,drag the chart into the layout of the report,you can't change the data set of the chart,or a error will occur. Actual result:A error occur when you change the data set] Expected result:You can change the data set.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/PropertySearchStrategy.java
*         is set.
	 */
	protected Object getSessionDefaultValue( Module module,
			ElementPropertyDefn prop )
	{
		if ( prop.isStyleProperty( ) )
		{
			
			return module.getSession( ).getDefaultValue( prop.getName( ) );
		}
		return null;
	}
	/**
	 * Tests if the property is inheritable in the context.
	 * 
	 * @param element
	 *            the element to test
	 * @param prop
	 *            definition of the property to test
	 * @return <code>true</code> if the property is inheritable in the
	 *         context, otherwise, <code>false</code>.
	 */
	protected boolean isInheritableProperty( DesignElement element,
			ElementPropertyDefn prop )
	{
		assert prop != null;
		return prop.canInherit( );
	}
}