But what do you want to do? To make it possible to select between Candle Open, Candle Close and all the others from the input parameters of the EA? Technically this is not impossible, but I don't have the enumerations that are needed for this.
That drop down for "Parameter" is a string variable and each position of "Parameter" has some value, but you don't know the value, so you don't know what to write in the Constant (in the input parameter of the EA).
And there is also a reason for why I don't want most of those drop down menus to be used as input parameters for the EA. A little bit hard to explain, but there is a good reason 🙂