Reporting Services question

I've created a dataset and report that has been running fine. Recently I modified the dataset, tested it OK, but was surprised the report shows nothing. Any clue why? thanks.I have read that after changeing a dataset - you have to refresh the schema
fromgotreportviewer.com...

There are two other common reasons to open the Report Data Sources dialog:

If a new field has been added to a datasource since it was added to the report, you have to press the Refresh All button before the report can "see" the new field.

You will also open this dialog to find out the names of report data sources.

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