I forgot to say that it is using asp.net mvc and the html5 viewer
answered on 01 May 2014, 01:11 PM
The described behavior is expected and the data from the data source is retrieved every time an Action has been executed.
The loading time when expanding/collapsing sections depends on a lot of different factors such as the amount of data retrieved from the data source, the available system resources, etc.
For more information on how to optimize your report, please follow the Performance Considerations help article.
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