Bug 167545 Copy a cascading parameter group and paste it to another parameter group causes an exception thrown
Steps to reproduce: 1.Copy a cascading parameter group using short cut key "Ctrl+x"/"Ctrl+c", or choosing context menu "Cut"/"Copy"; 2.Paste it to another parameter group using short cut key "Ctrl+v", or choosing context menu "Paste"; Expected result: The source one is pasted in the destination. Actual result: An exception thrown org.eclipse.birt.report.model.api.command.ContentException: The Cascading Parameter Group("Source") is not allowed in the slot (parameters) of Parameter Group("Destination").
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DEUtil.java
*/
	public static Iterator getStyles( )
	{
		return getStyles( new AlphabeticallyComparator( ) );
	}
	/**
	 * Get styles
	 * 
	 * @param comparator
	 * @return return styles list sortted with given comparator.
	 */
	public static Iterator getStyles( Comparator comparator )
	{
		List styles = null;
		if ( SessionHandleAdapter.getInstance( ).getReportDesignHandle( ) instanceof ReportDesignHandle )
		{
			styles = SessionHandleAdapter.getInstance( )
					.getReportDesignHandle( )
					.getAllStyles( );
		}
		else if ( SessionHandleAdapter.getInstance( ).getReportDesignHandle( ) instanceof LibraryHandle )
		{
			styles = new ArrayList( );
			ThemeHandle theme = ( (LibraryHandle) SessionHandleAdapter.getInstance( )
					.getReportDesignHandle( ) ).getTheme( );
			if ( theme != null )
			{
				styles.addAll( theme.getStyles( ).getContents( ) );
			}
		}