Hi Web Synergies,
Thank you for contacting Syncfusion support.
When setting GroupingMode as Multiple in DataGrid Xamarin.Forms, the additional column will render for the grouping, which is expected behavior in DataGrid. In which, the data is organized into hierarchical tree structure based on the identical values of that column. Based on the screenshot, we understand that you have added another TextColumn with smaller column width, so we can’t merge the header column and Grouping column.
We hope this helps. Please let us know, if you have any concern.
Regards,
Subburaj Pandian V