diff --git a/syncplay/ui/gui.py b/syncplay/ui/gui.py
index 9c88004..003f893 100755
--- a/syncplay/ui/gui.py
+++ b/syncplay/ui/gui.py
@@ -1480,7 +1480,7 @@ class MainWindow(QtWidgets.QMainWindow):
         self.listTreeView.setSelectionBehavior(QtWidgets.QAbstractItemView.SelectRows)
         self.listTreeView.customContextMenuRequested.connect(self.openRoomMenu)
         window.listlabel = QtWidgets.QLabel(getMessage("userlist-heading-label"))
-        if isMacOS:
+        if isMacOS():
             window.listlabel.setMinimumHeight(21)
             window.sslButton = QtWidgets.QPushButton(QtGui.QPixmap(resourcespath + 'lock_green.png').scaled(14, 14),"")
             window.sslButton.setVisible(False)