Thank you for the provided code snippet.
I need to point first that RadSyntaxEditor is complex control, and placing it in every cell of RadGridView will affect performance. In a scenario, when you want to show more complex information in the cell, I would recommend checking the RadGridView Row Details feature. The Row Details template provides a more compact layout. This way, you can show only needed information in the cell, and in the row details, you can add additional information about the expanded row.
In your case, you can place the RadSyntaxEditor inside the row details. For your convenience, I have prepared a sample project which demonstrates this approach.
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