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
private Label validateIcon = null;
	
	private Composite controller = null;
	private Label ano;
	private final HashMap selectionMap = new HashMap( );
	private boolean isModified;
	private Object editObject;
	/**
	 * Palette page
	 */
	public TreeViewPalettePage palettePage = new TreeViewPalettePage( );
	public ComboViewer cmbSubFunctionsViewer;
	
	private final IScriptEditor scriptEditor = createScriptEditor( );
	
	private ScriptValidator scriptValidator = null;
	
	private boolean isTextListenerEnable = true;
	
	private final ITextListener textListener = new ITextListener( ) {
		/*
		 * (non-Javadoc)
		 * 
		 * @see org.eclipse.jface.text.ITextListener#textChanged(org.eclipse.jface.text.TextEvent)
		 */
		public void textChanged( TextEvent event )
		{
			if ( isTextListenerEnable )
			{