diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -62,7 +62,6 @@
 find_package(KF5KIO ${KF5_MIN_VERSION} CONFIG REQUIRED)
 find_package(KF5TextWidgets ${KF5_MIN_VERSION} CONFIG REQUIRED)
 find_package(KF5WidgetsAddons ${KF5_MIN_VERSION} CONFIG REQUIRED)
-find_package(KF5WindowSystem ${KF5_MIN_VERSION} CONFIG REQUIRED)
 find_package(KF5XmlGui ${KF5_MIN_VERSION} CONFIG REQUIRED)
 find_package(KF5DBusAddons ${KF5_MIN_VERSION} CONFIG REQUIRED)
 find_package(KF5SyntaxHighlighting ${KF5_MIN_VERSION} CONFIG REQUIRED)
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -243,7 +243,6 @@
   Phonon::phonon4qt5
   KF5::XmlGui
   KF5::KIOWidgets
-  KF5::WindowSystem
   KF5::IconThemes
   KF5::Archive
   KF5::ItemViews
diff --git a/src/filter/kmfilterdialog.cpp b/src/filter/kmfilterdialog.cpp
--- a/src/filter/kmfilterdialog.cpp
+++ b/src/filter/kmfilterdialog.cpp
@@ -51,7 +51,6 @@
 #include <KMessageBox>
 #include <QPushButton>
 #include <QTabWidget>
-#include <KWindowSystem>
 #include <KIconButton>
 #include <QIcon>
 
@@ -104,11 +103,6 @@
     connect(buttonBox->button(QDialogButtonBox::Help), &QAbstractButton::clicked, this, &KMFilterDialog::slotHelp);
     setModal(false);
     okButton->setFocus();
-    KWindowSystem::setIcons(winId(),
-                            qApp->windowIcon().pixmap(IconSize(KIconLoader::Desktop),
-                                                      IconSize(KIconLoader::Desktop)),
-                            qApp->windowIcon().pixmap(IconSize(KIconLoader::Small),
-                                                      IconSize(KIconLoader::Small)));
     user1Button->setText(i18n("Import..."));
     user2Button->setText(i18n("Export..."));
     user3Button->setText(i18n("Convert to..."));
diff --git a/src/search/widgethandler/statusrulewidgethandler.cpp b/src/search/widgethandler/statusrulewidgethandler.cpp
--- a/src/search/widgethandler/statusrulewidgethandler.cpp
+++ b/src/search/widgethandler/statusrulewidgethandler.cpp
@@ -19,8 +19,8 @@
 #include "statusrulewidgethandler.h"
 #include "search/searchrule/searchrulestatus.h"
 
-#include <KIconLoader>
 #include <QComboBox>
+#include <QIcon>
 #include <QStackedWidget>
 
 using namespace MailCommon;
@@ -70,7 +70,7 @@
     for (int i = 0; i < MailCommon::StatusValueCountWithoutHidden; ++i) {
         if (MailCommon::StatusValues[ i ].icon != nullptr) {
             statusCombo->addItem(
-                SmallIcon(QLatin1String(MailCommon::StatusValues[ i ].icon)),
+                QIcon::fromTheme(QLatin1String(MailCommon::StatusValues[ i ].icon)),
                 i18nc("message status", MailCommon::StatusValues[ i ].text));
         } else {
             statusCombo->addItem(