Bug 148747 Design become invalid when I extend a masterpage from Library
The attachment contains a report file and a library file. Reproduce: 1. Deploy the library("lib"), and open the report. 2. Drag Masterpage("page1") from "lib" to report. 3. Reopen the report, it become invalid.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/writer/ModuleWriter.java
writeStructureList( obj, TemplateReportItem.VISIBILITY_PROP );
		writeUserPropertyDefns( obj );
		writeUserPropertyValues( obj );
		writer.endElement( );
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.elements.ElementVisitor#visitStyle(org.eclipse.birt.report.model.elements.Style)
	 */
	public void visitStyle( Style obj )
	{
		writer.startElement( DesignSchemaConstants.STYLE_TAG );
		super.visitStyle( obj );
		writeStyleProps( obj );
		writer.endElement( );
	}
	/**
	 * Write the style properties for either a shared style, or the "private
	 * style" for a styled element.
	 * 
	 * @param obj
	 *            the styled element
	 */
	private void writeStyleProps( DesignElement obj )
	{
		
		property( obj, Style.BACKGROUND_ATTACHMENT_PROP );
		property( obj, Style.BACKGROUND_COLOR_PROP );
		property( obj, Style.BACKGROUND_IMAGE_PROP );