Bug 191168 [Regression]Exception occurs when resize masterpage in library
Description: Exception occurs when resize masterpage in library. Build number:2.2.0.v20070606-0630 Regression bug:187443 Steps to reproduce: 1. New a library. 2. Go to Master Page, resize the master page using the ruler. Expected result: 1. Layout works correctly. 2. No exception is thrown out. Error log: An unexpected internal exception occurred.Please see log for detail. Plug-in Provider:Eclipse.org Plug-in Name:BIRT Designer UI Plug-in ID:org.eclipse.birt.report.designer.ui Version:2.2.0.v20070606-0630 Error Code:Error.GUIException.invokedByUnexpectedException Error Message:org.eclipse.birt.report.designer.internal.lib.lalyout.LibraryReportDesignLayout
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/Module.java
assert slot >= 0 && slot < getSlotCount( );
		return slots[slot];
	}
	/**
	 * Records a semantic error during build and similar batch operations. This
	 * implementation is preliminary.
	 * 
	 * @param ex
	 *            the exception to record
	 */
	public void semanticError( SemanticException ex )
	{
		if ( allExceptions == null )
			allExceptions = new ArrayList( );
		allExceptions.add( ex );
	}
	/**
	 * Returns a list containing all errors during parsing the module file.
	 * 
	 * @return a list containing parsing errors. Each element in the list is
	 *         <code>ErrorDetail</code>.
	 * 
	 * @see ErrorDetail
	 */
	public List getErrorList( )
	{
		List allErrors = getAllErrors( );
		List list = ErrorDetail.getSemanticErrors( allErrors,
				DesignFileException.DESIGN_EXCEPTION_SEMANTIC_ERROR );
		list.addAll( ErrorDetail.getSemanticErrors( allErrors,