diff --git a/aqt/addcards.py b/aqt/addcards.py
index 6d8f10f1a..5f53df5a5 100644
--- a/aqt/addcards.py
+++ b/aqt/addcards.py
@@ -18,7 +18,7 @@ import aqt.editor, aqt.modelchooser
 class AddCards(QDialog):
 
     def __init__(self, mw):
-        QDialog.__init__(self, mw, Qt.Window)
+        QDialog.__init__(self, None, Qt.Window)
         self.mw = mw
         self.form = aqt.forms.addcards.Ui_Dialog()
         self.form.setupUi(self)
diff --git a/aqt/browser.py b/aqt/browser.py
index 0fbe7a188..0d2bc899c 100644
--- a/aqt/browser.py
+++ b/aqt/browser.py
@@ -298,7 +298,7 @@ class StatusDelegate(QItemDelegate):
 class Browser(QMainWindow):
 
     def __init__(self, mw):
-        QMainWindow.__init__(self, mw)
+        QMainWindow.__init__(self, None, Qt.Window)
         applyStyles(self)
         self.mw = mw
         self.col = self.mw.col