Data provider is missing in the SqlDataSource Wizard.
|Product||Progress® Telerik® Reporting|
|Report Item||SqlDataSource component|
The list with ADO.NET providers is taken as described in Obtaining the DbProviderFactory article and lists all of the provider factories registered in the machine.config.
For instance, if MySQL provider is not registered correctly, but shows in Visual Studio, this means its installation has only registered it in Visual Studio and you can open devenv.exe.config to get the provider details and add it manually to the config file of the standalone designer(Telerik.ReportDesigner.exe.config).
If it is not listed in Visual Studio either, then most likely your installation of the MySQL ADO.NET provider did not complete successfully and you can try upgrading to a newer version, or repairing.