diff --git a/src/kitemviews/kitemlistcontroller.cpp b/src/kitemviews/kitemlistcontroller.cpp
--- a/src/kitemviews/kitemlistcontroller.cpp
+++ b/src/kitemviews/kitemlistcontroller.cpp
@@ -849,6 +849,9 @@
 {
     Q_UNUSED(event);
     Q_UNUSED(transform);
+
+    DragAndDropHelper::clearCacheUrlListMatchesUrl();
+
     return false;
 }
 
@@ -875,7 +878,6 @@
         return false;
     }
 
-
     QUrl hoveredDir = m_model->directory();
     KItemListWidget* oldHoveredWidget = hoveredWidget();
 
diff --git a/src/views/draganddrophelper.h b/src/views/draganddrophelper.h
--- a/src/views/draganddrophelper.h
+++ b/src/views/draganddrophelper.h
@@ -54,6 +54,16 @@
      * @return True if destUrl is contained in the urls parameter.
      */
     static bool urlListMatchesUrl(const QList<QUrl>& urls, const QUrl& destUrl);
+
+    /**
+     * clear the internal cache.
+     */
+    static void clearCacheUrlListMatchesUrl();
+private:
+    /**
+     * Stores the results of the expensive checks made in urlListMatchesUrl.
+     */
+    static QHash<QUrl, bool> m_cacheUrlListMatchesUrl;
 };
 
 #endif
diff --git a/src/views/draganddrophelper.cpp b/src/views/draganddrophelper.cpp
--- a/src/views/draganddrophelper.cpp
+++ b/src/views/draganddrophelper.cpp
@@ -29,12 +29,18 @@
 #include <KIO/DropJob>
 #include <KJobWidgets>
 
+QHash<QUrl, bool> DragAndDropHelper::m_cacheUrlListMatchesUrl;
 
 bool DragAndDropHelper::urlListMatchesUrl(const QList<QUrl>& urls, const QUrl& destUrl)
 {
-    return std::find_if(urls.constBegin(), urls.constEnd(), [destUrl](const QUrl& url) {
-        return url.matches(destUrl, QUrl::StripTrailingSlash);
-    }) != urls.constEnd();
+    if (!m_cacheUrlListMatchesUrl.contains(destUrl))
+    {
+        m_cacheUrlListMatchesUrl.insert(destUrl,
+            std::find_if(urls.constBegin(), urls.constEnd(), [destUrl](const QUrl& url) {
+                return url.matches(destUrl, QUrl::StripTrailingSlash);
+            }) != urls.constEnd() );
+    }
+    return m_cacheUrlListMatchesUrl[destUrl];
 }
 
 KIO::DropJob* DragAndDropHelper::dropUrls(const QUrl& destUrl, QDropEvent* event, QWidget* window)
@@ -53,7 +59,6 @@
         if (urlListMatchesUrl(event->mimeData()->urls(), destUrl)) {
             return nullptr;
         }
-
         // Drop into a directory or a desktop-file
         KIO::DropJob *job = KIO::drop(event, destUrl);
         KJobWidgets::setWindow(job, window);
@@ -63,3 +68,8 @@
     return nullptr;
 }
 
+void DragAndDropHelper::clearCacheUrlListMatchesUrl()
+{
+    DragAndDropHelper::m_cacheUrlListMatchesUrl.clear();
+}
+