Bug 122869 Drag a parameter from data explorer view into a table in library, a new parameter is created automatically.
Description:Drag a parameter from data explorer view into a table in library, a new parameter is created automatically. Steps to reproduce: 1. Add a cascading parameter and a table in a library file. 2. Drag a parameter from data explorer view into a table cell in layout editor. 3. Find that a new parameter was added in data explorer view automatically.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/dialogs/ExpressionTreeSupport.java
textWidget.insert( text );
		textWidget.setSelection( selectionStart + text.length( ) );
		textWidget.setFocus( );
		if ( text.endsWith( "()" ) ) 
		{
			textWidget.setCaretOffset( textWidget.getCaretOffset( ) - 1 ); 
		}
	}
	/**
	 * Adds drop support to viewer.Must set viewer before execution.
	 * 
	 */
	public void addDropSupportToViewer( )
	{
		Assert.isNotNull( expressionViewer );
		final StyledText text = expressionViewer.getTextWidget( );
		dropTarget = new DropTarget( text, DND.DROP_COPY | DND.DROP_DEFAULT );
		dropTarget.setTransfer( new Transfer[]{
			TextTransfer.getInstance( )
		} );
		dropTarget.addDropListener( new DropTargetAdapter( ) {
			public void dragEnter( DropTargetEvent event )
			{
				text.setFocus( );
				if ( event.detail == DND.DROP_DEFAULT )
					event.detail = DND.DROP_COPY;
				if ( event.detail != DND.DROP_COPY )
					event.detail = DND.DROP_NONE;
			}
			public void dragOver( DropTargetEvent event )