diff --git a/src/document/katedocument.h b/src/document/katedocument.h
--- a/src/document/katedocument.h
+++ b/src/document/katedocument.h
@@ -140,7 +140,7 @@
 
     QList<KTextEditor::View *> views() const Q_DECL_OVERRIDE
     {
-        return m_views.keys();
+        return m_viewsCache;
     }
 
     virtual KTextEditor::View *activeView() const
@@ -1405,6 +1405,10 @@
      * trigger a close of this document in the application
      */
     void closeDocumentInApplication();
+private:
+    // To calculate a QHash.keys() is quite expensive,
+    // better keep a copy of that list updated when a view is added or removed.
+    QList<KTextEditor::View *> m_viewsCache;
 };
 
 #endif
diff --git a/src/document/katedocument.cpp b/src/document/katedocument.cpp
--- a/src/document/katedocument.cpp
+++ b/src/document/katedocument.cpp
@@ -2832,6 +2832,7 @@
 {
     Q_ASSERT (!m_views.contains(view));
     m_views.insert(view, static_cast<KTextEditor::ViewPrivate *>(view));
+    m_viewsCache.append(view);
 
     // apply the view & renderer vars from the file type
     if (!m_fileType.isEmpty()) {
@@ -2848,6 +2849,7 @@
 {
     Q_ASSERT (m_views.contains(view));
     m_views.remove(view);
+    m_viewsCache.removeAll(view);
 
     if (activeView() == view) {
         setActiveView(nullptr);