Free Warp Tool

Hi everybody,
I open a new thread as I didn’t find an answer until now in the posts I’ve read.
My question is: why yellow warp markers appear only in certain tracks and not in others? What’s the criterium? I can’t understand…
I’m trying to record a guitar track where I strum chords just before the first bar beats and I want the peak fall exactly on it and as I wasn’t precise I wanted to adjust it but markers don’t appear…
Thank you for helping,