Bug 202254 Exception is thrown when category values are null and type of X axis is set to DateTime
chart/org.eclipse.birt.chart.ui.extension/src/org/eclipse/birt/chart/ui/swt/wizard/format/axis/AbstractAxisSubtask.java
{
				GridData gdBTNFormatSpecifier = new GridData( );
				gdBTNFormatSpecifier.widthHint = 20;
				gdBTNFormatSpecifier.heightHint = 20;
				gdBTNFormatSpecifier.horizontalIndent = -3;
				btnFormatSpecifier.setLayoutData( gdBTNFormatSpecifier );
				btnFormatSpecifier.setImage( UIHelper.getImage( "icons/obj16/formatbuilder.gif" ) ); 
				btnFormatSpecifier.setToolTipText( Messages.getString( "Shared.Tooltip.FormatSpecifier" ) ); 
				btnFormatSpecifier.addSelectionListener( this );
				btnFormatSpecifier.getImage( )
						.setBackground( btnFormatSpecifier.getBackground( ) );
			}
			
			if ( getChart( ).getDimension( ).getValue( ) != ChartDimension.THREE_DIMENSIONAL )
			{
				Label lblOrigin = new Label( cmpBasic, SWT.NONE );
				lblOrigin.setText( Messages.getString( "OrthogonalAxisDataSheetImpl.Lbl.Origin" ) ); 
				cmbOrigin = new Combo( cmpBasic, SWT.DROP_DOWN | SWT.READ_ONLY );
				{
					GridData gd = new GridData( );
					gd.widthHint = 220;
					gd.horizontalSpan = 2;
					cmbOrigin.setLayoutData( gd );
					cmbOrigin.addSelectionListener( this );
				}
				boolean bValueOrigin = false;
				if ( getAxisForProcessing( ).getOrigin( ) != null )
				{
					if ( getAxisForProcessing( ).getOrigin( )
							.getType( )