Index: src/kio/kfiledialog.cpp
===================================================================
--- src/kio/kfiledialog.cpp
+++ src/kio/kfiledialog.cpp
@@ -326,8 +326,6 @@
 void KFileDialog::setMimeFilter(const QStringList &mimeTypes,
                                 const QString &defaultType)
 {
-    d->w->setMimeFilter(mimeTypes, defaultType);
-
     if (d->native) {
         QString allExtensions;
         QStringList filters = mime2KdeFilter(mimeTypes, &allExtensions);
@@ -335,7 +333,9 @@
             filters.prepend(allExtensions + QLatin1Char('|') + i18n("All Supported Files"));
         }
         d->native->filter = filters.join(QLatin1String("\n"));
+        return;
     }
+    d->w->setMimeFilter(mimeTypes, defaultType);
 }

 void KFileDialog::clearFilter()
@@ -385,6 +385,9 @@
 // This is only used for the initial size when no configuration has been saved
 QSize KFileDialog::sizeHint() const
 {
+    if (d->native) {
+        return QSize();
+    }
     return d->w->dialogSizeHint();
 }

@@ -601,7 +604,7 @@

 void KFileDialog::setConfirmOverwrite(bool enable)
 {
-    if (operationMode() == KFileDialog::Saving) {
+    if (d->w && operationMode() == KFileDialog::Saving) {
         d->w->setConfirmOverwrite(enable);
     }
 }
@@ -869,43 +872,57 @@

 QPushButton *KFileDialog::okButton() const
 {
-    return d->w->okButton();
+    if (d->w) {
+        return d->w->okButton();
+    }
+    return nullptr;
 }

 QPushButton *KFileDialog::cancelButton() const
 {
-    return d->w->cancelButton();
+    if (d->w) {
+        return d->w->cancelButton();
+    }
+    return nullptr;
 }

 KUrlComboBox *KFileDialog::locationEdit() const
 {
-    return d->w->locationEdit();
+    if (d->w) {
+        return d->w->locationEdit();
+    }
+    return nullptr;
 }

 KFileFilterCombo *KFileDialog::filterWidget() const
 {
-    return d->w->filterWidget();
+    if (d->w) {
+        return d->w->filterWidget();
+    }
+    return nullptr;
 }

 KActionCollection *KFileDialog::actionCollection() const
 {
-    return d->w->actionCollection();
+    if (d->w) {
+        return d->w->actionCollection();
+    }
+    return nullptr;
 }

 void KFileDialog::setKeepLocation(bool keep)
 {
-    if (d->native) {
-        return;
+    if (d->w) {
+        d->w->setKeepLocation(keep);
     }
-    d->w->setKeepLocation(keep);
 }

 bool KFileDialog::keepsLocation() const
 {
-    if (d->native) {
-        return false;
+    if (d->w) {
+        return d->w->keepsLocation();
     }
-    return d->w->keepsLocation();
+    return false;
 }

 void KFileDialog::setOperationMode(OperationMode mode)
@@ -927,27 +944,23 @@

 void KFileDialog::keyPressEvent(QKeyEvent *e)
 {
-    if (d->native) {
-        return;
-    }
-
-    if (e->key() == Qt::Key_Escape) {
-        e->accept();
-        d->w->cancelButton()->animateClick();
-    } else {
-        QDialog::keyPressEvent(e);
+    if (d->w) {
+        if (e->key() == Qt::Key_Escape) {
+            e->accept();
+            d->w->cancelButton()->animateClick();
+        } else {
+            QDialog::keyPressEvent(e);
+        }
     }
 }

 void KFileDialog::hideEvent(QHideEvent *e)
 {
-    if (d->native) {
-        return;
-    }
+    if (d->w) {
+        KWindowConfig::saveWindowSize(windowHandle(), d->cfgGroup, KConfigBase::Persistent);

-    KWindowConfig::saveWindowSize(windowHandle(), d->cfgGroup, KConfigBase::Persistent);
-
-    QDialog::hideEvent(e);
+        QDialog::hideEvent(e);
+    }
 }

 // static
@@ -967,7 +980,10 @@

 KToolBar *KFileDialog::toolBar() const
 {
-    return d->w->toolBar();
+    if (d->w) {
+        return d->w->toolBar();
+    }
+    return nullptr;
 }

 KFileWidget *KFileDialog::fileWidget()