Thanks for your update.
Regarding Multiple cell Selection:
Once the cell enters in to the edit mode of any data templated cell means, you cannot perform multiple selection by dragging. Because, here selection will be control by that corresponding data templated control and also grid cannot predicted which controls is inside the data templated cell. But, you can achieve this multiple selection behavior for data templated cells by using CellItemtemplate and CellEdItItemTemplate and by setting syncfusion:VisualContainer.WantsMouseInput property as False like shown be.
For displaying the highlighted cell, you achieve by using the below code snippet,
dataGrid.DrawSelectionOptions = GridDrawSelectionOptions.AlphaBlend;
dataGrid.HighlightSelectionAlphaBlend = Brushes.Red;
Once the data templated cell enters into edit mode, even though you select multiple cells in the grid , only the respective edit mode cell content will be copied to the clipboard. For instance, You can observe that behavior while debugging by using below code,
And also please note, In GridDatacontrol copy paste will be applied based on the DataType of the Mapping Name of the GridDataControl.
For your reference, please find sample and video in the below location,
Similar query is posted in the incident #82877. For further calrification, please update your queries in the incident #82877 for better follow up.
Please let us know if you have any queries.