This is UI bug which was missed by MS QA team.
Steps to produce
1. Create a classifier function
CREATE FUNCTION dbo.RG_Classifier_2() RETURNS sysname
WITH SCHEMABINDING
AS
BEGIN
DECLARE @grp_name sysname
IF (DB_NAME() = 'Sales')
SET @grp_name = 'GroupSales'
IF (DB_NAME() = 'Reports')
SET @grp_name = 'GroupReports'
IF (SUSER_NAME() LIKE 'DataW')
SET @grp_name = 'GroupDWH'
RETURN @grp_name
END;
GO
-- Register the classifier function with Resource Governor
ALTER RESOURCE GOVERNOR WITH (CLASSIFIER_FUNCTION= dbo.RG_Classifier_2);
GO
-- Start Resource Governor
ALTER RESOURCE GOVERNOR RECONFIGURE;
GO
2. Create another classifier function
CREATE FUNCTION dbo.RG_Classifier_3() RETURNS sysname
WITH SCHEMABINDING
AS
BEGIN
DECLARE @grp_name sysname
IF (DB_NAME() = 'Sales')
SET @grp_name = 'GroupSales'
IF (DB_NAME() = 'Reports')
SET @grp_name = 'GroupReports'
IF (SUSER_NAME() LIKE 'DataW')
SET @grp_name = 'GroupDWH'
RETURN @grp_name
END;
GO
-- Register the classifier function with Resource Governor
ALTER RESOURCE GOVERNOR WITH (CLASSIFIER_FUNCTION= dbo.RG_Classifier_3);
GO
-- Start Resource Governor
ALTER RESOURCE GOVERNOR RECONFIGURE;
GO
3. Go to properties of Resource Governor.
All classifier functions in the drop down while last one is selected with Enable Resource Governor option is selected.
4. Select some other classifier function name and above option is disabled.
5. Select the previous classifier function again where enable resource governor should be enable where as it is disable.
If you cancel the screen and come back to the same dialog box it will be enable as it should be.
