diff --git a/qutebrowser/completion/completer.py b/qutebrowser/completion/completer.py
index 92e774ed2..71202d131 100644
--- a/qutebrowser/completion/completer.py
+++ b/qutebrowser/completion/completer.py
@@ -241,8 +241,8 @@ class Completer(QObject):
         else:
             return s
 
-    @pyqtSlot(QItemSelection, QItemSelection)
-    def on_selection_changed(self, selected, _deselected):
+    @pyqtSlot(QItemSelection)
+    def on_selection_changed(self, selected):
         """Change the completed part if a new item was selected.
 
         Called from the views selectionChanged method.
diff --git a/qutebrowser/completion/completionwidget.py b/qutebrowser/completion/completionwidget.py
index 8feefffd9..9fc1ef5d7 100644
--- a/qutebrowser/completion/completionwidget.py
+++ b/qutebrowser/completion/completionwidget.py
@@ -104,7 +104,7 @@ class CompletionView(QTreeView):
     """
 
     resize_completion = pyqtSignal()
-    selection_changed = pyqtSignal(QItemSelection, QItemSelection)
+    selection_changed = pyqtSignal(QItemSelection)
 
     def __init__(self, win_id, parent=None):
         super().__init__(parent)
@@ -255,7 +255,7 @@ class CompletionView(QTreeView):
     def selectionChanged(self, selected, deselected):
         """Extend selectionChanged to call completers selection_changed."""
         super().selectionChanged(selected, deselected)
-        self.selection_changed.emit(selected, deselected)
+        self.selection_changed.emit(selected)
 
     def resizeEvent(self, e):
         """Extend resizeEvent to adjust column size."""
diff --git a/tests/unit/completion/test_completer.py b/tests/unit/completion/test_completer.py
index c5b4ccdf8..29196ea3b 100644
--- a/tests/unit/completion/test_completer.py
+++ b/tests/unit/completion/test_completer.py
@@ -216,6 +216,6 @@ def test_on_selection_changed(before, newtxt, count, quick_complete, after,
     _set_cmd_prompt(status_command_stub, before)
     # schedule_completion_update is needed to pick up the cursor position
     completer_obj.schedule_completion_update()
-    completer_obj.on_selection_changed(selection, None)
+    completer_obj.on_selection_changed(selection)
     model.data.assert_called_with(indexes[0])
     _validate_cmd_prompt(status_command_stub, after)