improvements

mne/viz/_3d.py

@@ -1025,7 +1025,7 @@ def _handle_sensor_types(meg, eeg, fnirs):
         fnirs=dict(channels="fnirs", pairs="fnirs_pairs"),
     )
     sensor_alpha = {
-        key: dict(meg_helmet=0.25, meg=0.25).get(key, 0.8)
+        key: dict(meg_helmet=0.25, meg=0.25).get(key, 1.0)
         for ch_dict in alpha_map.values()
         for key in ch_dict.values()
     }