diff --git a/src/editor/attachment/attachmentview.h b/src/editor/attachment/attachmentview.h
--- a/src/editor/attachment/attachmentview.h
+++ b/src/editor/attachment/attachmentview.h
@@ -77,6 +77,7 @@
     QToolButton *mToolButton = nullptr;
     QLabel *mInfoAttachment = nullptr;
     QWidget *mWidget = nullptr;
+    KConfigGroup grp;
 };
 } // namespace KMail
 
diff --git a/src/editor/attachment/attachmentview.cpp b/src/editor/attachment/attachmentview.cpp
--- a/src/editor/attachment/attachmentview.cpp
+++ b/src/editor/attachment/attachmentview.cpp
@@ -51,6 +51,7 @@
 
 AttachmentView::AttachmentView(MessageComposer::AttachmentModel *model, QWidget *parent)
     : QTreeView(parent)
+    , grp(KMKernel::self()->config()->group("AttachmentView"))
 {
     mWidget = new QWidget();
     QHBoxLayout *lay = new QHBoxLayout(mWidget);
@@ -100,13 +101,11 @@
 
 void AttachmentView::restoreHeaderState()
 {
-    KConfigGroup grp(KMKernel::self()->config(), "AttachmentView");
     header()->restoreState(grp.readEntry("State", QByteArray()));
 }
 
 void AttachmentView::saveHeaderState()
 {
-    KConfigGroup grp(KMKernel::self()->config(), "AttachmentView");
     grp.writeEntry("State", header()->saveState());
     grp.sync();
 }
diff --git a/src/editor/kmcomposerwin.cpp b/src/editor/kmcomposerwin.cpp
--- a/src/editor/kmcomposerwin.cpp
+++ b/src/editor/kmcomposerwin.cpp
@@ -520,12 +520,13 @@
 
     mDummyComposer = new MessageComposer::Composer(this);
     mDummyComposer->globalPart()->setParentWidgetForGui(this);
+
+    KConfigGroup grp(KMKernel::self()->config()->group("Composer"));
+    setAutoSaveSettings(grp, true);
 }
 
 KMComposerWin::~KMComposerWin()
 {
-    writeConfig();
-
     // When we have a collection set, store the message back to that collection.
     // Note that when we save the message or sent it, mFolder is set back to 0.
     // So this for example kicks in when opening a draft and then closing the window.
@@ -665,8 +666,6 @@
     KMailSettings::self()->setComposerSize(size());
     KMailSettings::self()->setShowSnippetManager(mSnippetAction->isChecked());
 
-    KConfigGroup grp(KMKernel::self()->config()->group("Composer"));
-    saveMainWindowSettings(grp);
     if (mSnippetAction->isChecked()) {
         KMailSettings::setSnippetSplitterPosition(mSnippetSplitter->sizes());
     }
@@ -1731,6 +1730,7 @@
         return false;
     }
     if (kmkernel->shuttingDown() || qApp->isSavingSession()) {
+        writeConfig();
         return true;
     }
 
@@ -1770,6 +1770,7 @@
         qCWarning(KMAIL_LOG) << "Tried to close while composer was active";
         return false;
     }
+    writeConfig();
     return true;
 }
 
@@ -3049,8 +3050,6 @@
 
 void KMComposerWin::slotEditToolbars()
 {
-    KConfigGroup grp(KMKernel::self()->config()->group("Composer"));
-    saveMainWindowSettings(grp);
     QPointer<KEditToolBar> dlg = new KEditToolBar(guiFactory(), this);
 
     connect(dlg.data(), &KEditToolBar::newToolBarConfig, this, &KMComposerWin::slotUpdateToolbars);
diff --git a/src/kmkernel.cpp b/src/kmkernel.cpp
--- a/src/kmkernel.cpp
+++ b/src/kmkernel.cpp
@@ -1063,33 +1063,14 @@
 
 void KMKernel::closeAllKMailWindows()
 {
-    QList<KMainWindow *> windowsToDelete;
-
     foreach (KMainWindow *window, KMainWindow::memberList()) {
         if (::qobject_cast<KMMainWin *>(window)
             || ::qobject_cast<KMail::SecondaryWindow *>(window)) {
             // close and delete the window
             window->setAttribute(Qt::WA_DeleteOnClose);
             window->close();
-            windowsToDelete.append(window);
         }
     }
-
-    // We delete all main windows here. Above we called close(), but that calls
-    // deleteLater() internally, therefore does not delete it immediately.
-    // This would lead to problems when closing Kontact when a composer window
-    // is open, because the destruction order is:
-    //
-    // 1. destructor of the Kontact mainwinow
-    // 2.   delete all parts
-    // 3.     the KMail part destructor calls KMKernel::cleanup(), which calls
-    //        this function
-    // 4. delete all other mainwindows
-    //
-    // Deleting the composer windows here will make sure that step 4 will not delete
-    // any composer window, which would fail because the kernel is already deleted.
-    qDeleteAll(windowsToDelete);
-    windowsToDelete.clear();
 }
 
 void KMKernel::cleanup(void)