+ QSet<QString> extensions;
+ foreach (const KFileItem& item, m_items) {
+ const QString extension = KMimeType::extractKnownExtension(item.url().toDisplayString().toLower());
+
+ if (extensions.contains(extension)) {
+ m_allExtensionsDifferent = false;
+ break;
+ }
+
+ extensions.insert(extension);
+ }
+