Tacx training doesn't show zones while workout with trainer

I'm confused... I've had a training program running for few days now, and there is some power based training and then just basic cycllng in status "bike" in Tacx Training App during the workout. But if the program tells that I have to ride for 2 hours at z2, how I know what that means? Is it power zone, or HR zone? And as Garmin knows both of my zones (they are in Garmin Connect settings, and that workout plan was created with Garmin Connect) why it doesn't put that value into Tacx Training App so that it would show in graph which area my power/HR should be? Because it tells that information in normal training showing bars in different heights and adjust resistant based on those. But why not in every kind of workouts?!?