I have a couple of app subscriptions for UG and Songsterr. It doesn't show what strings to not play, like some tabs I've seen printed. Sometimes there will be an X in the middle of some notes and I figure that means to mute that string. However, if some of these multi-note formations are chords, how do you know what strings not to hit (for example, if you are not supposed to hit the low E or high E, they never seem to be X'd out)? Am I supposed to assume every string that doesn't have a fret number gets played as an open string?

Am I making sense? Or do I need to attempt a drawing with dashes and numbers?