diff --git a/app/documentinfoprovider.h b/app/documentinfoprovider.h
--- a/app/documentinfoprovider.h
+++ b/app/documentinfoprovider.h
@@ -45,10 +45,6 @@
 
     virtual void thumbnailForDocument(const QUrl &url, ThumbnailGroup::Enum group, QPixmap* outPix, QSize* outFullSize) const Q_DECL_OVERRIDE;
 
-private Q_SLOTS:
-    void emitBusyStateChanged(const QUrl&, bool);
-    void emitDocumentChanged(const QUrl&);
-
 private:
     SortedDirModel* mDirModel;
 };
diff --git a/app/documentinfoprovider.cpp b/app/documentinfoprovider.cpp
--- a/app/documentinfoprovider.cpp
+++ b/app/documentinfoprovider.cpp
@@ -37,11 +37,10 @@
 : AbstractDocumentInfoProvider(model)
 {
     mDirModel = model;
-    connect(DocumentFactory::instance(), SIGNAL(documentBusyStateChanged(QUrl,bool)),
-            SLOT(emitBusyStateChanged(QUrl,bool)));
-
-    connect(DocumentFactory::instance(), SIGNAL(documentChanged(QUrl)),
-            SLOT(emitDocumentChanged(QUrl)));
+    connect(DocumentFactory::instance(), &DocumentFactory::documentBusyStateChanged,
+            this, &AbstractDocumentInfoProvider::busyStateChanged);
+    connect(DocumentFactory::instance(), &DocumentFactory::documentChanged,
+            this, &AbstractDocumentInfoProvider::documentChanged);
 }
 
 void DocumentInfoProvider::thumbnailForDocument(const QUrl &url, ThumbnailGroup::Enum group, QPixmap* outPix, QSize* outFullSize) const
@@ -89,22 +88,4 @@
     }
 }
 
-void DocumentInfoProvider::emitBusyStateChanged(const QUrl &url, bool busy)
-{
-    QModelIndex index = mDirModel->indexForUrl(url);
-    if (!index.isValid()) {
-        return;
-    }
-    busyStateChanged(index, busy);
-}
-
-void DocumentInfoProvider::emitDocumentChanged(const QUrl &url)
-{
-    QModelIndex index = mDirModel->indexForUrl(url);
-    if (!index.isValid()) {
-        return;
-    }
-    documentChanged(index);
-}
-
 } // namespace
diff --git a/lib/thumbnailview/abstractdocumentinfoprovider.h b/lib/thumbnailview/abstractdocumentinfoprovider.h
--- a/lib/thumbnailview/abstractdocumentinfoprovider.h
+++ b/lib/thumbnailview/abstractdocumentinfoprovider.h
@@ -57,8 +57,8 @@
     virtual void thumbnailForDocument(const QUrl &url, ThumbnailGroup::Enum, QPixmap* outPix, QSize* outFullSize) const = 0;
 
 Q_SIGNALS:
-    void busyStateChanged(const QModelIndex&, bool);
-    void documentChanged(const QModelIndex&);
+    void busyStateChanged(const QUrl& url, bool busy);
+    void documentChanged(const QUrl& url);
 };
 
 } // namespace
diff --git a/lib/thumbnailview/thumbnailview.h b/lib/thumbnailview/thumbnailview.h
--- a/lib/thumbnailview/thumbnailview.h
+++ b/lib/thumbnailview/thumbnailview.h
@@ -190,14 +190,14 @@
     void setBrokenThumbnail(const KFileItem&);
 
     /**
-     * Generate thumbnail for @a index.
+     * Generate thumbnail for url.
      */
-    void updateThumbnail(const QModelIndex& index);
+    void updateThumbnail(const QUrl& url);
 
     /**
-     * Tells the view the busy state of the document pointed by the index has changed.
+     * Tells the view the busy state of the document pointed by the url has changed.
      */
-    void updateThumbnailBusyState(const QModelIndex& index, bool);
+    void updateThumbnailBusyState(const QUrl& url, bool);
 
     /*
      * Cause a repaint of all busy indexes
diff --git a/lib/thumbnailview/thumbnailview.cpp b/lib/thumbnailview/thumbnailview.cpp
--- a/lib/thumbnailview/thumbnailview.cpp
+++ b/lib/thumbnailview/thumbnailview.cpp
@@ -447,10 +447,10 @@
 {
     d->mDocumentInfoProvider = provider;
     if (provider) {
-        connect(provider, SIGNAL(busyStateChanged(QModelIndex,bool)),
-                SLOT(updateThumbnailBusyState(QModelIndex,bool)));
-        connect(provider, SIGNAL(documentChanged(QModelIndex)),
-                SLOT(updateThumbnail(QModelIndex)));
+        connect(provider, &AbstractDocumentInfoProvider::busyStateChanged,
+                this, &ThumbnailView::updateThumbnailBusyState);
+        connect(provider, &AbstractDocumentInfoProvider::documentChanged,
+                this, &ThumbnailView::updateThumbnail);
     }
 }
 
@@ -869,22 +869,29 @@
     }
 }
 
-void ThumbnailView::updateThumbnail(const QModelIndex& index)
+void ThumbnailView::updateThumbnail(const QUrl& url)
 {
-    KFileItem item = fileItemForIndex(index);
-    QUrl url = item.url();
+    const ThumbnailForUrl::Iterator it = d->mThumbnailForUrl.find(url);
+    if (it == d->mThumbnailForUrl.end()) {
+        return;
+    }
+
     if (d->mDocumentInfoProvider && d->mDocumentInfoProvider->isModified(url)) {
-        d->updateThumbnailForModifiedDocument(index);
+        d->updateThumbnailForModifiedDocument(it->mIndex);
     } else {
-        KFileItemList list;
-        list << item;
-        d->appendItemsToThumbnailProvider(list);
+        const KFileItem item = fileItemForIndex(it->mIndex);
+        d->appendItemsToThumbnailProvider(KFileItemList({ item }));
     }
 }
 
-void ThumbnailView::updateThumbnailBusyState(const QModelIndex& _index, bool busy)
+void ThumbnailView::updateThumbnailBusyState(const QUrl& url, bool busy)
 {
-    QPersistentModelIndex index(_index);
+    const ThumbnailForUrl::Iterator it = d->mThumbnailForUrl.find(url);
+    if (it == d->mThumbnailForUrl.end()) {
+        return;
+    }
+
+    QPersistentModelIndex index(it->mIndex);
     if (busy && !d->mBusyIndexSet.contains(index)) {
         d->mBusyIndexSet << index;
         update(index);