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
.getSystemColor( SWT.COLOR_LIST_FOREGROUND ) );
						}
						( (ComputedColumnHandle) element ).setName( newName );
						if ( selectedNameChanged )
						{
							selectedColumnName = newName;
						}
					}
				}
				else
				{
					ComputedColumnHandle bindingHandle = ( (ComputedColumnHandle) element );
					if ( COLUMN_DATATYPE.equals( property ) )
					{
						bindingHandle.setDataType( dataTypes[( (Integer) value ).intValue( )].getName( ) );
					}
					else if ( COLUMN_EXPRESSION.equals( property ) )
					{
						bindingHandle.setExpression( (String) value );
					}
					else if ( COLUMN_AGGREGATEON.equals( property ) )
					{
						if ( ( (Integer) value ).intValue( ) == 0 )
							bindingHandle.setAggregrateOn( null );
						else
							bindingHandle.setAggregrateOn( groups[( (Integer) value ).intValue( )] );
					}
				}
			}
			catch ( SemanticException e )