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.
chart/org.eclipse.birt.chart.ui.extension/src/org/eclipse/birt/chart/ui/swt/composites/TriggerDataComposite.java
1,
				Messages.getString( "TriggerDataComposite.Label.VisiblityDescription" ) ); 
		
		cmpDPVisibility = new Composite( grpValue, SWT.NONE );
		cmpDPVisibility.setLayout( new GridLayout( ) );
		addDescriptionLabel( cmpDPVisibility,
				1,
				Messages.getString( "TriggerDataComposite.Label.DPVisibilityDescription" ) ); 
		
		cmpScript = new Composite( grpValue, SWT.NONE );
		cmpScript.setLayout( new GridLayout( 2, false ) );
		Label lblScript = new Label( cmpScript, SWT.NONE );
		{
			GridData gdLBLScript = new GridData( GridData.VERTICAL_ALIGN_BEGINNING );
			lblScript.setLayoutData( gdLBLScript );
			lblScript.setText( Messages.getString( "TriggerDataComposite.Lbl.Script" ) ); 
		}
		txtScript = new Text( cmpScript, SWT.MULTI | SWT.BORDER | SWT.V_SCROLL );
		{
			GridData gd = new GridData( GridData.FILL_BOTH );
			gd.verticalSpan = 2;
			txtScript.setLayoutData( gd );
			txtScript.setToolTipText( Messages.getString( "TriggerDataComposite.Tooltip.InputScript" ) ); 
		}
		btnScriptExpBuilder = new Button( cmpScript, SWT.PUSH );
		{
			GridData gd = new GridData( );
			gd.heightHint = 20;
			gd.widthHint = 20;
			gd.verticalAlignment = GridData.BEGINNING;