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
/**
	 * Removes one dispose listener. If the listener not registered, then the
	 * request is silently ignored.
	 * 
	 * @param listener
	 *            the dispose listener to remove
	 * @return <code>true</code> if <code>listener</code> is successfully
	 *         removed. Otherwise <code>false</code>.
	 * 
	 */
	public boolean removeDisposeListener( IDisposeListener listener )
	{
		if ( disposeListeners == null )
			return false;
		return disposeListeners.remove( listener );
	}
	/**
	 * Removes one resource change listener. If the listener not registered,
	 * then the request is silently ignored.
	 * 
	 * @param listener
	 *            the resource change listener to remove
	 * @return <code>true</code> if <code>listener</code> is successfully
	 *         removed. Otherwise <code>false</code>.
	 * 
	 */
	public boolean removeResourceChangeListener(
			IResourceChangeListener listener )
	{
		if ( resourceChangeListeners == null )