Zooming in Bluestacks is 'flaky'. Click the keyboard icon, click the zoom function, then assign plain keys - say Z and X - to in and out. Go to a track edit, click/drag a little, then hit the 'zoom in' key a couple of times. If nothing happens, click-drag a bit, then try again. Zooming out is much worse than zooming in for me (Z=out, X=in on mine) and usually I just hit the 'full track' icon to zoom out, then the 'track decor' icon to zoom in to that scale, then back to track edit. To get detailed placement of anchors (or kerbs) from there, I tap the zoom in key repeatedly until happy. In the kerbs/clutter screens, I've noticed this occasionally jumps around the track and even deletes/moves your carefully placed stuff, so keep an eye on things.