diff --git a/startkde/startplasma.cpp b/startkde/startplasma.cpp
--- a/startkde/startplasma.cpp
+++ b/startkde/startplasma.cpp
@@ -185,28 +185,18 @@
     }
     sourceFiles(scripts);
 
-    // If the kde installation is in a non-standard location (ie. with a dev build),
-    // it is possible the data root is not in the XDG_DATA_DIRS variable yet.
-    // If that's the case prepend it to the value. Prepending ensures this kde
-    // installation's resources will get preference over another one whose prefix
-    // is also in the XDG_DATA_DIRS variable, like a system installation in
-    // /usr/share.
-    //
-    // If our data root is already in the XDG_DATA_DIRS variable do nothing. This
-    // includes leaving it unset if it was unset. By doing nothing in this case
-    // we don't mess with the preference order implied by the value.
+    // To ensure the proper resources are available, the data root dir
+    // needs to be available in the XDG_DATA_DIRS variable, with
+    // the right preference.
     QString xdgDataDirsValue;
     if (qEnvironmentVariableIsSet("XDG_DATA_DIRS")) {
         xdgDataDirsValue = QString::fromLocal8Bit(qgetenv("XDG_DATA_DIRS"));
     } else {
-        // If the environment variable is unset, the spec says to assume
-        // this value. Set it here, so we can still perform the regular
-        // check on the value even though the value was unset.
         xdgDataDirsValue = QLatin1String("/usr/local/share:/usr/share");
     }
-    QString kdeInstallFullDataRootDir = QStringLiteral(KDE_INSTALL_FULL_DATAROOTDIR);
-    QStringList xdgDataDirs = xdgDataDirsValue.split(QLatin1Char(':'));
-    if (!xdgDataDirs.contains(kdeInstallFullDataRootDir)) {
+    const QString kdeInstallFullDataRootDir = QStringLiteral(KDE_INSTALL_FULL_DATAROOTDIR);
+    QVector<QStringRef> xdgDataDirs = xdgDataDirsValue.splitRef(QLatin1Char(':'));
+    if (!xdgDataDirs.contains(QStringRef(&kdeInstallFullDataRootDir))) {
         QString xdgDataDirsNewValue = kdeInstallFullDataRootDir + QLatin1Char(':') + xdgDataDirsValue;
         qputenv("XDG_DATA_DIRS", xdgDataDirsNewValue.toLocal8Bit());
     }