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
{
			setResult( selectedColumnName );
			if ( inputElement instanceof DataItemHandle )
			{
				try
				{
					( (DataItemHandle) inputElement ).setResultSetColumn( selectedColumnName );
				}
				catch ( SemanticException e )
				{
					ExceptionHandler.handle( e );
				}
			}
		}
		super.okPressed( );
	}
	private void deleteRow( ComputedColumnHandle handle )
	{
		try
		{
			if ( handle.getName( ).equals( selectedColumnName ) )
			{
				selectedColumnName = null;
			}
			handle.drop( );
			refreshBindingTable( );
		}
		catch ( PropertyValueException e )
		{
			ExceptionHandler.handle( e );