Bug 182673 No default value error message prompts incorrectly
Steps to reproduce: 1. New a report parameter; 2. Choose control type as Combo; 3. Choose parameter as dynamic type; Expected result: As the isRequired is false by default, parameter's default value can be null value. There should be no error message about no default value prompt. Actual result; Error messages prompts
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ParameterDialog.java
{
				
				type = PARAM_CONTROL_LIST;
			}
			else
			{
				
				type = PARAM_CONTROL_COMBO;
			}
		}
		else
		{
			type = inputParameter.getControlType( );
		}
		return type;
	}
	private String getSelectedDataType( )
	{
		String type = null;
		if ( StringUtil.isBlank( dataTypeChooser.getText( ) ) )
		{
			type = inputParameter.getDataType( );
		}
		else
		{
			IChoice choice = DATA_TYPE_CHOICE_SET.findChoiceByDisplayName( dataTypeChooser.getText( ) );
			type = choice.getName( );
		}
		return type;
	}