Report Dataset is lost once the Data Tab is clicked

1. Created a New Report Server Wizard Project using OLAP as datasource
2. Gone through the wizard steps to generate a matrix report.
3. All is fine and the report gets previewed. I build and deploy the report.
4. Now , if I need to add a new column I go to data tab of the report. Realize that the query is lost and now the report throws exception like the following when rebuild:

" [rsFieldReference] The Value expression for the textbox ‘Base_Premium’ refers to the field ‘Base_Premium’. Report item expressions can only refer to fields within the current data set scope or, if inside an aggregate, the specified data set scope."
5. No idea why the query given at the query builder stage of the wizard is lost

Steps to Reproduce:

1. Create a new Report Server Wizard Project
2. Create a new datasource using OLAP as datasource
3. Add the report data fields (query builder)
4. Select matrix report format and any style
5. Select the row, col and data fields.
6. complete the wizard.
7. Save, build and deploy the project
8. Preview the report.
9. Now try to add a new column to the report by clicking the data tab.

Actual Results:

The sql prepared from the query builder is lost and all the columns previously selected disappear. The report throws exception in preview mode something like :

" [rsFieldReference] The Value expression for the textbox ‘Base_Premium’ refers to the field ‘Base_Premium’. Report item expressions can only refer to fields within the current data set scope or, if inside an aggregate, the specified data set scope."

Expected Results:

Should be able to modify the report any number of times after it is initially generated.

Actual Results:

The sql prepared from the query builder is lost and all the columns previously selected disappear. The report throws exception in preview mode something like :

" [rsFieldReference] The Value expression for the textbox ‘Base_Premium’ refers to the field ‘Base_Premium’. Report item expressions can only refer to fields within the current data set scope or, if inside an aggregate, the specified data set scope."

Expected Results:

Should be able to modify the report any number of times after it is initially generated.

Please check this KB article: http://support.microsoft.com/kb/909535/en-us