diff --git a/spikeinterface_gui/mergeview.py b/spikeinterface_gui/mergeview.py
index 1a6169f..66712ea 100644
--- a/spikeinterface_gui/mergeview.py
+++ b/spikeinterface_gui/mergeview.py
@@ -270,7 +270,7 @@ def _qt_make_layout(self):
 
     def _qt_refresh(self):
         from .myqt import QT
-        from .utils_qt import CustomItem
+        from .utils_qt import CustomItem, CustomItemUnitID
 
         self.table.clear()
         self.table.setSortingEnabled(False)
@@ -287,6 +287,7 @@ def _qt_refresh(self):
         self.table.setColumnCount(len(labels))
         self.table.setHorizontalHeaderLabels(labels)
         self.table.setRowCount(len(rows))
+        unit_ids = self.controller.unit_ids
 
         for r, row in enumerate(rows):
             for c, label in enumerate(labels):
@@ -298,7 +299,7 @@ def _qt_refresh(self):
                     pix = QT.QPixmap(16, 16)
                     pix.fill(color)
                     icon = QT.QIcon(pix)
-                    item = QT.QTableWidgetItem(name)
+                    item = CustomItemUnitID(unit_ids, name)
                     item.setData(QT.Qt.ItemDataRole.UserRole, unit_id)
                     item.setFlags(QT.Qt.ItemIsEnabled | QT.Qt.ItemIsSelectable)
                     self.table.setItem(r, c, item)
diff --git a/spikeinterface_gui/utils_qt.py b/spikeinterface_gui/utils_qt.py
index 4f18dd3..123508f 100644
--- a/spikeinterface_gui/utils_qt.py
+++ b/spikeinterface_gui/utils_qt.py
@@ -470,10 +470,14 @@ def __init__(self, unit_ids, *args, **kwargs):
         self.unit_ids = [f"{u}" for u in unit_ids]
 
     def __lt__(self, other):
-        ind = self.unit_ids.index(self.text())
-        other_ind = self.unit_ids.index(other.text())
+        # since mergeview has "{unit_id} (n={n_spikes})" as name, we split and keep the first part
+        unit_id = self.text().split(' ')[0]
+        other_unit_id = other.text().split(' ')[0]
+        ind = self.unit_ids.index(unit_id)
+        other_ind = self.unit_ids.index(other_unit_id)
         return ind < other_ind
 
+
 class OrderableCheckItem(QT.QTableWidgetItem):
     # special case for checkbox
     def is_checked(self):