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/LineAttributesComposite.java
flMain.marginWidth = 0;
		GridLayout glContent = new GridLayout( );
		glContent.verticalSpacing = 5;
		glContent.horizontalSpacing = 5;
		glContent.marginHeight = 4;
		glContent.marginWidth = 4;
		glContent.numColumns = 6;
		this.setLayout( flMain );
		cmpContent = new Composite( this, SWT.NONE );
		cmpContent.setLayout( glContent );
		bEnabled = laCurrent.isVisible( );
		boolean bEnableUI = bEnabled;
		if ( bEnableVisibility )
		{
			cbVisible = new Button( cmpContent, SWT.CHECK );
			GridData gdCBVisible = new GridData( GridData.FILL_HORIZONTAL );
			gdCBVisible.horizontalSpan = 6;
			cbVisible.setLayoutData( gdCBVisible );
			cbVisible.setText( Messages.getString( "LineAttributesComposite.Lbl.IsVisible" ) ); 
			cbVisible.setSelection( laCurrent.isVisible( ) );
			cbVisible.addSelectionListener( this );
			if ( bEnabled )
			{
				bEnableUI = cbVisible.getSelection( );
			}
		}
		if ( bEnableStyles )
		{
			lblStyle = new Label( cmpContent, SWT.NONE );
			GridData gdLStyle = new GridData( GridData.HORIZONTAL_ALIGN_BEGINNING );