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
{
	/**
	 * The low-level writer that emits XML syntax.
	 */
	/**
	 * The constant for default model name space.
	 */
	final protected static String DEFAULT_NAME_SPACE = "http://www.eclipse.org/birt/2005/design"; 
	/**
	 * The XML writer.
	 */
	protected IndentableXMLWriter writer = null;
	/**
	 * The base 64 codec for embedded images.
	 */
	protected static Base64 base = new Base64( );
	/**
	 * The compatibility to create bound columns.
	 */
	protected BoundColumnsWriterMgr boundColumnsMgr = null;
	/**
	 * Returns the module to write.
	 * 
	 * @return the module to write
	 */
	abstract protected Module getModule( );
	/**
	 * Writes the report design to a file.