Currently, there is no way to optimize an input that takes a boolean (true/false) as a parameter. When you attempt to optimize a signal that has a boolean input, that input is not shown in the "optimize inputs" dialog box. Rather, the signal will be optimized using whatever value you have currently applied for that signal.
  
E.g., assume that you have a signal with two inputs, with the following defaults:
  
   MovingAverageLength (100),
   AllowShortTrades(false);
  
If you attempt to optimize this signal, only the "MovingAverageLength" input will show up in the "optimize inputs" dialog box. It won't be obvious that there's a second input, "AllowShortTrades," and there isn't any way to run an optimization that uses values of both "false" and "true" for that input.
  
There's one workaround, namely using numbers as inputs in place of boolean values. I.e., to define the input with a default value of "0" instead of "false," and then use either "0" or "1" as an input to represent "false" and "true." Then you can optimize for both false and true by entering a range of "0 to 1" for that input in the "optimize inputs" dialog box. However, this isn't a great coding practice.
  
It would be better if MultiCharts could instead display boolean inputs in the "optimize inputs" dialog box, and give users a choice about whether to optimize those inputs. In that case, the user should be given options between something like "only true," "only false," or "both true and false" as the values for optimization. I.e., the user can force that input to be "true" for every simulation (without optimizing that particular input), "false" for every simulation (same), or optimized using values of "true" for some simulations runs and "false" for others.