diff --git a/openlp/core/__init__.py b/openlp/core/__init__.py
index 5de5e69de..cb298e11b 100644
--- a/openlp/core/__init__.py
+++ b/openlp/core/__init__.py
@@ -375,6 +375,7 @@ def main(args=None):
     application.setOrganizationName('OpenLP')
     application.setOrganizationDomain('openlp.org')
     application.setAttribute(QtCore.Qt.AA_UseHighDpiPixmaps, True)
+    application.setAttribute(QtCore.Qt.AA_DontCreateNativeWidgetSiblings, True)
     if args and args.portable:
         application.setApplicationName('OpenLPPortable')
         Settings.setDefaultFormat(Settings.IniFormat)
diff --git a/openlp/core/ui/themewizard.py b/openlp/core/ui/themewizard.py
index 95262cf8f..7eac787d9 100644
--- a/openlp/core/ui/themewizard.py
+++ b/openlp/core/ui/themewizard.py
@@ -44,9 +44,9 @@ class Ui_ThemeWizard(object):
         theme_wizard.setModal(True)
         theme_wizard.setOptions(QtWidgets.QWizard.IndependentPages |
                                 QtWidgets.QWizard.NoBackButtonOnStartPage | QtWidgets.QWizard.HaveCustomButton1)
+        theme_wizard.setFixedWidth(640)
         if is_macosx():
             theme_wizard.setPixmap(QtWidgets.QWizard.BackgroundPixmap, QtGui.QPixmap(':/wizards/openlp-osx-wizard.png'))
-            theme_wizard.resize(646, 400)
         else:
             theme_wizard.setWizardStyle(QtWidgets.QWizard.ModernStyle)
         self.spacer = QtWidgets.QSpacerItem(10, 0, QtWidgets.QSizePolicy.Fixed, QtWidgets.QSizePolicy.Minimum)