I am in the Grove, right by a map marker for an "undiscovered vista." There seems to be nothing special about it except for a nearby balcony. There seems to be no apparent trigger around except for a discussion tree with Nikkyta (which apparently I've known since forever except I'm not even born yet, but that's a matter for a different day.)
So... what am I missing here?
Vistas are often in hard to reach places above the ground, most likely on a roof or on top of a stone formation. To reach it, there should be a more or less obvious path leading to this place, often requiring a few jumps.
The specific marker to trigger a vista is a small light shaft with a vista icon floating above. You just need to be in the light and press F in order to trigger it. The hard part is both locating and reaching the vista itself.
In this specific example, the answer is directly in front of your eyes:
