I had setted parameters for expressions of my custom behavior in v51/52.
It was working as when double clicking the expression in the expression list, the expression would appear followed by ("name_of_parameter") for a string param for example.
As of r53 and now r54, the expression appears, but not with the parameter.
AddNumberParam("x", "getBoard[x]", "1");
AddNumberParam("y", "getBoard[y]", "1");
AddExpression(5, ef_return_string, "Get Board[x][y]", "Results", "getBoard", "Get the content of the cell at submitted X,Y. (1 = obstacle, w = walkable, S = start, D = destination");
When double clicked from the expression list window appears as :
And you have to add the parameters by yourself.
If you try to use it as it, the tooltip will tell you it is missing parameters and that 2 are expected. But it doesn't appear from the moment you chose it.