Hi Roger,
Thanks for using Syncfusion products.
We have analyzed your reported scenario at our end. The reported error may be occurred due to the assemblies are not referred properly to the GridGroupingControl. Please check whether you are properly referred the following dependencies,
Note:
Please check whether the assemblies are installed in the GAC. If its not installed then manually refer the assemblies by using the reference path,
<InstalledLocation>Syncfusion\Essential Studio\[VersionNo]\precompiledassemblies\[VersionNo]\[AssemblyVersion]\
For example,
C:\Program Files (x86)\Syncfusion\Essential Studio\14.1.0.46\precompiledassemblies\14.1.0.46\4.5.1\
Regards,
Adhi