diff --git a/src/spikeanalysis/spike_plotter.py b/src/spikeanalysis/spike_plotter.py
index 85cf1b7..9269f0e 100644
--- a/src/spikeanalysis/spike_plotter.py
+++ b/src/spikeanalysis/spike_plotter.py
@@ -528,7 +528,7 @@ def plot_sm_fr(
                 keep_list.append(np.where(cluster_indices == cid)[0][0])
             keep_list = np.array(keep_list)
         else:
-            keep_list = np.arange(0, len(cluster_indices), 1)
+            keep_list = np.arange(0, len(self.data.cluster_ids), 1)
 
         stim_trial_groups = self._get_trial_groups()
         event_lengths = self._get_event_lengths_all()