Bug 141959 Changing data set didn't clean old column bindings
Steps to reproduce: 1.Add two data sets, "ds1" and "ds2" 2.Add a table, binding with "ds1". All "ds1" column bindings generate automatically, that's good 3.Change "ds1" to None Expected result: All "ds1" column bindings should be cleaned Actual result: All "ds1" column bindings are still there. If changing to "ds2", "ds2" column bindings will be added after them.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ColumnBindingDialog.java
protected void addBinding( ComputedColumn column )
	{
		try
		{
			DEUtil.addColumn( DEUtil.getBindingHolder( inputElement ),
					column,
					false );
		}
		catch ( SemanticException e )
		{
			ExceptionHandler.handle( e );
		}
	}
	protected List getBindingList( DesignElementHandle inputElement )
	{
		return DEUtil.getVisiableColumnBindingsList( inputElement );
	}
	private boolean canChangeDataSet( String newName )
	{
		String currentDataSetName = getDataSetName( );
		if ( NONE.equals( currentDataSetName ) )
		{
			return true;
		}
		else if ( !currentDataSetName.equals( newName ) )
		{
			return MessageDialog.openQuestion( null,
					Messages.getString( "dataBinding.title.changeDataSet" ), Messages.getString( "dataBinding.message.changeDataSet" ) ); 
		}
		return false;