I'm using the Periodic timer interrupt LDD component in PE on a Kinetis K20. I'm trying to turn on the "SetPeriodUS", "SetFrequencyHz", etc. methods, but they are greyed out, saying that I need to go to "Runtime setting type" and set it to "from interval". When I go to properties->Interrupt period->Runtime setting type and the only option is "fixed value". How can I enable the methods I want?