Bug 390669 [Accessibility]Press 'Tab' doesn't focus on the next report item when adding relative period aggregation.
xtab/org.eclipse.birt.report.item.crosstab.ui/src/org/eclipse/birt/report/item/crosstab/internal/ui/dialogs/CrosstabBindingDialogHelper.java
&& recentButton.getSelection( ) )
					{
						this.messageLine.setText( Messages.getString( "CrosstabBindingDialogHelper.timeperiod.wrongdate" ) ); 
						this.messageLine.setImage( PlatformUI.getWorkbench( )
								.getSharedImages( )
								.getImage( ISharedImages.IMG_OBJS_ERROR_TSK ) );
						dialog.setCanFinish( false );
						return;
					}
					if ( dateSelectionButton.getSelection( )
							&& ( dateText.getText( ) == null || dateText.getText( )
									.trim( )
									.equals( "" ) ) ) 
					{
						dialog.setCanFinish( false );
						return;
					}
				}
				else
				{
					dialog.setCanFinish( false );
					return;
				}
			}
			dialogCanFinish( );
		}
		updateRemoveBtnState( );
	}
	private void dialogCanFinish( )
	{