Bug 166315 Combo box doesn't allow blank when set string type in parameter editor
Combo box doesn't allow blank when set string type in parameter editor Steps to reproduce: 1.New a parameter, display type is Combo Box 2.Select data type as String Expected result: "Allow blank values" is enable. Actual result: "Allow blank values" is gray and can't be checked.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ParameterDialog.java
}
		return v1.equals( v2 );
	}
	private Object getValue( String value ) throws BirtException
	{
		if ( DesignChoiceConstants.PARAM_TYPE_BOOLEAN.equals( getSelectedDataType( ) ) )
		{
			return DataTypeUtil.toBoolean( value );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_DECIMAL.equals( getSelectedDataType( ) ) )
		{
			return DataTypeUtil.toBigDecimal( value );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_DATETIME.equals( getSelectedDataType( ) ) )
		{
			return DataTypeUtil.toDate( value, ULocale.US );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_FLOAT.equals( getSelectedDataType( ) ) )
		{
			return DataTypeUtil.toDouble( value );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_INTEGER.equals( getSelectedDataType( ) ) )
		{
			return DataTypeUtil.toInteger( value );
		}
		return value;
	}
	private IChoiceSet getFormatChoiceSet( String type )
	{
		IChoiceSet choiceSet = null;