[vis] Avoid unnecessary stacking

phi/vis/_vis.py

@@ -403,7 +403,7 @@ def _space(*values: Field or Tensor, ignore_dims: Shape, log_dims: Tuple[str], e
     if '_' in all_dims and len(all_dims) > 2:
         all_dims.remove('_')
     all_bounds = [embed(get_default_limits(f, all_dims, log_dims, e).without(ignore_dims.names).largest(shape), all_dims) for f, e in zip(values, errs)]
-    bounds: Box = math.stack(all_bounds, batch('_fields'))
+    bounds: Box = math.stack(all_bounds, batch('_fields'), simplify=True)
     lower = math.finite_min(bounds.lower, bounds.shape.without('vector'), default=-math.INF)
     upper = math.finite_max(bounds.upper, bounds.shape.without('vector'), default=math.INF)
     return Box(lower, upper)