fix orientation getting messed up, move to arrow rendering

src/blik/reader.py

@@ -60,9 +60,11 @@ def _construct_orientations_layer(coords, features, scale, exp_id, p_id, source)
         {
             "name": f"{exp_id} - particle orientations",
             "edge_color": vec_color,
-            "length": 150 / np.array(scale),
+            "length": 100 / np.array(scale),
+            "edge_width": 10 / np.array(scale),
             "scale": [scale] * 3,
             "metadata": {"experiment_id": exp_id, "p_id": p_id, "source": source},
+            "vector_style": "arrow",
             # "projection_mode": "all",  # only available in napari 0.5.0
             "out_of_slice_display": True,
         },
@@ -102,8 +104,9 @@ def construct_particle_layer_tuples(
     )
     ori = _construct_orientations_layer(coords, features, scale, exp_id, p_id, source)
 
-    # invert order for convenience (latest added layer is selected)
-    return [ori, pos]
+    # ori should be last, or the auto-update feedback loop messes up the orientations
+    # when existing layers are updated from a new run
+    return [pos, ori]
 
 
 def read_particles(particles):

src/blik/widgets/picking.py

@@ -173,14 +173,13 @@ def surface_particles(
     pos = np.concatenate(pos)
     features = pd.DataFrame({"orientation": np.asarray(Rotation.concatenate(ori))})
 
-    vec_layer_tuple, pos_layer_tuple = construct_particle_layer_tuples(
+    return construct_particle_layer_tuples(
         coords=invert_xyz(pos),
         features=features,
         scale=surface.scale[0],
         exp_id=exp_id,
         face_color_cycle=colors,
     )
-    return [vec_layer_tuple, pos_layer_tuple]
 
 
 @magicgui(
@@ -280,13 +279,12 @@ def filament_particles(
 
     features = pd.DataFrame({"orientation": np.asarray(Rotation.concatenate(ori))})
 
-    vec_layer_tuple, pos_layer_tuple = construct_particle_layer_tuples(
+    return construct_particle_layer_tuples(
         coords=invert_xyz(pos),
         features=features,
         scale=filament.scale[0],
         exp_id=exp_id,
     )
-    return [vec_layer_tuple, pos_layer_tuple]
 
 
 @magicgui(