Ramifications of changing an SSRS report with Report Builder that was originally developed in Report Designer

If I change a complex SSRS report using Report Builder that was originally developed using Report Designer, is it possible that some functionality will be lost?

I understand that Report Designer is more feature rich and the concern is that I would inadvertently wipe out something that would otherwise be okay if I were to edit it using Report Designer.

I think the mainly differences about compatibility can be sumarized as below:

• Create Shared Datasources is not possible in Report Builder. I am not sure if Report Builder can handle this feature from a RDL file generated from Report Designer.
• Use local custom .NET Framework assemblies in languages such as VB.NET or C# is possible from Report Designer but in Report Builder is not possible. It is possible Report Builder does not recognize your report custom code if any function was created in Report Designer.
• If you want to import your report from Access it is also not possible in Report Builder.

Reference

Let me know if this helps.