diff --git a/kcmkwin/kwindesktop/desktop.cpp b/kcmkwin/kwindesktop/desktop.cpp
index e0ead129ca..a7f2e02a25 100644
--- a/kcmkwin/kwindesktop/desktop.cpp
+++ b/kcmkwin/kwindesktop/desktop.cpp
@@ -138,11 +138,11 @@ KDesktopConfig::KDesktopConfig(QWidget *parent, const QVariantList &)
 
   KSharedConfig::Ptr config = KSharedConfig::openConfig( "kwinrc" );
 
-  QString groupname;
+  QByteArray groupname;
   if (kwin_screen_number == 0)
      groupname = "Desktops";
   else
-     groupname = "Desktops-screen-" + QString::number ( kwin_screen_number );
+     groupname = "Desktops-screen-" + QByteArray::number ( kwin_screen_number );
 
   if (config->isGroupImmutable(groupname))
   {
@@ -151,7 +151,7 @@ KDesktopConfig::KDesktopConfig(QWidget *parent, const QVariantList &)
   }
   else
   {
-     KConfigGroup cfgGroup(config.data(), groupname);
+     KConfigGroup cfgGroup(config.data(), groupname.constData());
      if (cfgGroup.isEntryImmutable("Number"))
      {
         number_group->setEnabled(false);