Hi Patrick,
Here is the work around. To have the transparent color in the ColorEdit celltype, you have to use the custom celltype. This celltype as to be derived from the DropDownCellModel and DropDownCellRenderer. The DropDownCellModel class handles the serialization requirements for the control and creates the renderer class and the DropDownCellRenderer class handles the UI requirements of the cell. Kindly refer to the
sample for more details.
Let us know if you need further assistance,
Regards,
Madhan