Bug 201042 [Accessibility]Chart scritp should not add by auto when click the down in keyboard[17]
Description: Chart scritp should not add by auto when click the down in keyboard[0704] Step: 1. New a chart and switch to script view. 2. Let the point on the script function selection. 3. Click the down on keyboard. Actual result: A function will add by auto. Expected result: Customer can not select the function under the second function by keyboard, and it should not be added by auto.
UI/org.eclipse.birt.report.designer.ui.editors.schematic/src/org/eclipse/birt/report/designer/internal/ui/editors/script/JSEditor.java
* @see org.eclipse.birt.report.designer.core.util.mediator.IColleague#performRequest(org.eclipse.birt.report.designer.core.util.mediator.request.ReportRequest)
	 */
	public void performRequest( ReportRequest request )
	{
		if ( ReportRequest.SELECTION.equals( request.getType( ) ) )
		{
			handleSelectionChange( request.getSelectionModelList( ) );
		}
		if ( ReportRequest.CREATE_ELEMENT.equals( request.getType( ) )
				&& request.getSelectionModelList( ).get( 0 ) instanceof ScriptDataSourceHandle )
		{
			handleSelectionChange( request.getSelectionModelList( ) );
		}
	}
	private void setComboViewerInput( Object model )
	{
		cmbExprListViewer.setInput( model );
		Object oldSelection = selectionMap.get( model );
		if ( oldSelection == null )
		{
			selectItemInComboExpList( new StructuredSelection( ) );
		}
		else
		{
			selectItemInComboExpList( (ISelection) oldSelection );
		}
		cmbSubFunctionsViewer.setInput( model );
		int itemCount = cmbSubFunctions.getItemCount( );
		if ( itemCount > 0 )
		{