We are experimenting with drag and drop in the Universal GUI and it looks really promising.  For a certain application we are trying to link rows from one grid to rows in another grid. This works fine but we don’t want to allow users to drag a row to another row that is already linked. Is this possible? Using the context logic disables it for the entire table. We could of course show a message using the task logic and use conditional formatting to make it more intuitive but I’ve seen the cursor change to a forbidden sign while dragging across other tables. Is this something we can program as well?

Also, if a user can’t find a match in the target table while dragging, we would like to allow them to drop the row on the table rather than a row so we can create a row for them. I can’t seem to get this to work, the drag and drop task parameters get filled with target row columns wherever I release the drag.
The docs mention the following:

Does this mean it is possible to drag to the table rather than a row but I need to do something differently?