My mistake was to change JSON at panel level.
In reality I must set “type=table-old” at dashboard level.
I have managed to switch my table to an “old” style and to hide a column.
But when the column is hidden, it can not be used in data-links.
This is not funny actually.
New table is sexy, but it forbits HTML or markdown inside a cell.
Old table allows HTML (at least I see a partial support of this feature),
but it ignores my attempts to color a text in the cell.
Thank you for your response!
At least now I can choose between “bad new table” and “bad old table”. =)