list of fields not refreshed/updated after I change my query in the dataset

Hi,

I have an embeded dataset in my SSRS  report (using visual studio 2012),

I modify my dataset query adding 2 fields in my select statement, however, when i try to add the newly added fields to my report, I see that the list of available dataset fields remains the same. Available Data set fields is not updated to match the new returned fields by the new query. Any idea pls ??

Thank you :)