Hi Peter,
Thanks for using Syncfusion Products.
By default Groups in Grid Data Control will not expand when clicked on the last item of the previous group. In general Groups in Grid Data Control can expand only when click on the expander or call the ExpandAll() or ExpandAllGroups() explicitly. For your convenience, we have prepared a sample based on this. please check the sample with your scenario. If still you face the problem, please revert us by modifying the sample based on your application. This will help us to provide better assistance.
Sample:
http://www.syncfusion.com/uploads/redirect.aspx?&team=support&file=Sample1712756888.zip Please let us know if this helps.
Regards,
Manikandan