diff --git a/src/Splitter.cpp b/src/Splitter.cpp
index 32c67425d428c837df902dcb315078b3f8d3921a..6267e59195d8ad6886438b390c35cc0b24a97f77 100644
--- a/src/Splitter.cpp
+++ b/src/Splitter.cpp
@@ -15,15 +15,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <QApplication>
-#include <QDesktopWidget>
 #include <QSettings>
-#include <QShortcut>
 
-#include "Config.h"
 #include "Logging.h"
 #include "Splitter.h"
-#include "Utils.h"
 
 constexpr auto MaxWidth = (1 << 24) - 1;
 
@@ -180,4 +175,3 @@ splitter::calculateSidebarSizes(const QFont &f)
 
         return sz;
 }
-
diff --git a/src/TextInputWidget.h b/src/TextInputWidget.h
index 2f267a23d7703b2f12fac65c09bfd910923ec609..3674ee0d8ab905ab29624a9fec986bca0c0655f4 100644
--- a/src/TextInputWidget.h
+++ b/src/TextInputWidget.h
@@ -18,17 +18,14 @@
 #pragma once
 
 #include <deque>
-#include <iterator>
-#include <map>
 #include <optional>
 
-#include <QApplication>
+#include <QCoreApplication>
 #include <QHBoxLayout>
 #include <QPaintEvent>
 #include <QTextEdit>
 #include <QWidget>
 
-#include "Utils.h"
 #include "dialogs/PreviewUploadOverlay.h"
 #include "emoji/PickButton.h"
 #include "popups/ReplyPopup.h"
diff --git a/src/Utils.cpp b/src/Utils.cpp
index 55eebbc97ad86e2bf7c42a84b7d32c6ba84ee222..91ecfcd783711ca3467d35fc2f07916fd8de5af0 100644
--- a/src/Utils.cpp
+++ b/src/Utils.cpp
@@ -651,4 +651,3 @@ utils::restoreCombobox(QComboBox *combo, const QString &value)
                 }
         }
 }
-
diff --git a/src/dialogs/PreviewUploadOverlay.cpp b/src/dialogs/PreviewUploadOverlay.cpp
index 31d0121406645a992c9a96f24333927f751d31c6..42558d679bf00d559c662e1368efd6a4f383def5 100644
--- a/src/dialogs/PreviewUploadOverlay.cpp
+++ b/src/dialogs/PreviewUploadOverlay.cpp
@@ -15,7 +15,6 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <QApplication>
 #include <QBuffer>
 #include <QFile>
 #include <QFileInfo>
diff --git a/src/popups/UserMentions.cpp b/src/popups/UserMentions.cpp
index 763eeffc2bde4a8a8972d8bb05d27a4162638054..b0223f7fb79cf19d6770df0581d835896320017b 100644
--- a/src/popups/UserMentions.cpp
+++ b/src/popups/UserMentions.cpp
@@ -1,7 +1,10 @@
+#include <QPaintEvent>
 #include <QPainter>
+#include <QScrollArea>
 #include <QStyleOption>
 #include <QTabWidget>
 #include <QTimer>
+#include <QVBoxLayout>
 
 #include "Cache.h"
 #include "ChatPage.h"
diff --git a/src/popups/UserMentions.h b/src/popups/UserMentions.h
index 42bdcd60796450bab2f9059b31a4896a70e59d6b..b7c4e51d4ffb0db34e51155c30850da296f37a6b 100644
--- a/src/popups/UserMentions.h
+++ b/src/popups/UserMentions.h
@@ -3,13 +3,13 @@
 #include <mtx/responses.hpp>
 
 #include <QMap>
-#include <QPaintEvent>
-#include <QScrollArea>
 #include <QString>
-#include <QTabWidget>
-#include <QVBoxLayout>
 #include <QWidget>
 
+class QPaintEvent;
+class QTabWidget;
+class QScrollArea;
+class QVBoxLayout;
 
 namespace popups {
 
diff --git a/src/ui/DropShadow.cpp b/src/ui/DropShadow.cpp
index 93baa02d36474637009357e018b5870363c89589..d437975ccbc63caa0f3cf8f3d8d1f54f67263fe2 100644
--- a/src/ui/DropShadow.cpp
+++ b/src/ui/DropShadow.cpp
@@ -3,108 +3,106 @@
 #include <QLinearGradient>
 #include <QPainter>
 
+void
+DropShadow::draw(QPainter &painter,
+                 qint16 margin,
+                 qreal radius,
+                 QColor start,
+                 QColor end,
+                 qreal startPosition,
+                 qreal endPosition0,
+                 qreal endPosition1,
+                 qreal width,
+                 qreal height)
+{
+        painter.setPen(Qt::NoPen);
 
-        void DropShadow::draw(QPainter &painter,
-                         qint16 margin,
-                         qreal radius,
-                         QColor start,
-                         QColor end,
-                         qreal startPosition,
-                         qreal endPosition0,
-                         qreal endPosition1,
-                         qreal width,
-                         qreal height)
-        {
-                painter.setPen(Qt::NoPen);
+        QLinearGradient gradient;
+        gradient.setColorAt(startPosition, start);
+        gradient.setColorAt(endPosition0, end);
 
-                QLinearGradient gradient;
-                gradient.setColorAt(startPosition, start);
-                gradient.setColorAt(endPosition0, end);
+        // Right
+        QPointF right0(width - margin, height / 2);
+        QPointF right1(width, height / 2);
+        gradient.setStart(right0);
+        gradient.setFinalStop(right1);
+        painter.setBrush(QBrush(gradient));
+        // Deprecated in 5.13: painter.drawRoundRect(
+        //  QRectF(QPointF(width - margin * radius, margin), QPointF(width, height -
+        //  margin)), 0.0, 0.0);
+        painter.drawRoundedRect(
+          QRectF(QPointF(width - margin * radius, margin), QPointF(width, height - margin)),
+          0.0,
+          0.0);
 
-                // Right
-                QPointF right0(width - margin, height / 2);
-                QPointF right1(width, height / 2);
-                gradient.setStart(right0);
-                gradient.setFinalStop(right1);
-                painter.setBrush(QBrush(gradient));
-                // Deprecated in 5.13: painter.drawRoundRect(
-                //  QRectF(QPointF(width - margin * radius, margin), QPointF(width, height -
-                //  margin)), 0.0, 0.0);
-                painter.drawRoundedRect(
-                  QRectF(QPointF(width - margin * radius, margin), QPointF(width, height - margin)),
-                  0.0,
-                  0.0);
+        // Left
+        QPointF left0(margin, height / 2);
+        QPointF left1(0, height / 2);
+        gradient.setStart(left0);
+        gradient.setFinalStop(left1);
+        painter.setBrush(QBrush(gradient));
+        painter.drawRoundedRect(
+          QRectF(QPointF(margin * radius, margin), QPointF(0, height - margin)), 0.0, 0.0);
 
-                // Left
-                QPointF left0(margin, height / 2);
-                QPointF left1(0, height / 2);
-                gradient.setStart(left0);
-                gradient.setFinalStop(left1);
-                painter.setBrush(QBrush(gradient));
-                painter.drawRoundedRect(
-                  QRectF(QPointF(margin * radius, margin), QPointF(0, height - margin)), 0.0, 0.0);
+        // Top
+        QPointF top0(width / 2, margin);
+        QPointF top1(width / 2, 0);
+        gradient.setStart(top0);
+        gradient.setFinalStop(top1);
+        painter.setBrush(QBrush(gradient));
+        painter.drawRoundedRect(
+          QRectF(QPointF(width - margin, 0), QPointF(margin, margin)), 0.0, 0.0);
 
-                // Top
-                QPointF top0(width / 2, margin);
-                QPointF top1(width / 2, 0);
-                gradient.setStart(top0);
-                gradient.setFinalStop(top1);
-                painter.setBrush(QBrush(gradient));
-                painter.drawRoundedRect(
-                  QRectF(QPointF(width - margin, 0), QPointF(margin, margin)), 0.0, 0.0);
+        // Bottom
+        QPointF bottom0(width / 2, height - margin);
+        QPointF bottom1(width / 2, height);
+        gradient.setStart(bottom0);
+        gradient.setFinalStop(bottom1);
+        painter.setBrush(QBrush(gradient));
+        painter.drawRoundedRect(
+          QRectF(QPointF(margin, height - margin), QPointF(width - margin, height)), 0.0, 0.0);
 
-                // Bottom
-                QPointF bottom0(width / 2, height - margin);
-                QPointF bottom1(width / 2, height);
-                gradient.setStart(bottom0);
-                gradient.setFinalStop(bottom1);
-                painter.setBrush(QBrush(gradient));
-                painter.drawRoundedRect(
-                  QRectF(QPointF(margin, height - margin), QPointF(width - margin, height)),
-                  0.0,
-                  0.0);
+        // BottomRight
+        QPointF bottomright0(width - margin, height - margin);
+        QPointF bottomright1(width, height);
+        gradient.setStart(bottomright0);
+        gradient.setFinalStop(bottomright1);
+        gradient.setColorAt(endPosition1, end);
+        painter.setBrush(QBrush(gradient));
+        painter.drawRoundedRect(QRectF(bottomright0, bottomright1), 0.0, 0.0);
 
-                // BottomRight
-                QPointF bottomright0(width - margin, height - margin);
-                QPointF bottomright1(width, height);
-                gradient.setStart(bottomright0);
-                gradient.setFinalStop(bottomright1);
-                gradient.setColorAt(endPosition1, end);
-                painter.setBrush(QBrush(gradient));
-                painter.drawRoundedRect(QRectF(bottomright0, bottomright1), 0.0, 0.0);
+        // BottomLeft
+        QPointF bottomleft0(margin, height - margin);
+        QPointF bottomleft1(0, height);
+        gradient.setStart(bottomleft0);
+        gradient.setFinalStop(bottomleft1);
+        gradient.setColorAt(endPosition1, end);
+        painter.setBrush(QBrush(gradient));
+        painter.drawRoundedRect(QRectF(bottomleft0, bottomleft1), 0.0, 0.0);
 
-                // BottomLeft
-                QPointF bottomleft0(margin, height - margin);
-                QPointF bottomleft1(0, height);
-                gradient.setStart(bottomleft0);
-                gradient.setFinalStop(bottomleft1);
-                gradient.setColorAt(endPosition1, end);
-                painter.setBrush(QBrush(gradient));
-                painter.drawRoundedRect(QRectF(bottomleft0, bottomleft1), 0.0, 0.0);
+        // TopLeft
+        QPointF topleft0(margin, margin);
+        QPointF topleft1(0, 0);
+        gradient.setStart(topleft0);
+        gradient.setFinalStop(topleft1);
+        gradient.setColorAt(endPosition1, end);
+        painter.setBrush(QBrush(gradient));
+        painter.drawRoundedRect(QRectF(topleft0, topleft1), 0.0, 0.0);
 
-                // TopLeft
-                QPointF topleft0(margin, margin);
-                QPointF topleft1(0, 0);
-                gradient.setStart(topleft0);
-                gradient.setFinalStop(topleft1);
-                gradient.setColorAt(endPosition1, end);
-                painter.setBrush(QBrush(gradient));
-                painter.drawRoundedRect(QRectF(topleft0, topleft1), 0.0, 0.0);
+        // TopRight
+        QPointF topright0(width - margin, margin);
+        QPointF topright1(width, 0);
+        gradient.setStart(topright0);
+        gradient.setFinalStop(topright1);
+        gradient.setColorAt(endPosition1, end);
+        painter.setBrush(QBrush(gradient));
+        painter.drawRoundedRect(QRectF(topright0, topright1), 0.0, 0.0);
 
-                // TopRight
-                QPointF topright0(width - margin, margin);
-                QPointF topright1(width, 0);
-                gradient.setStart(topright0);
-                gradient.setFinalStop(topright1);
-                gradient.setColorAt(endPosition1, end);
-                painter.setBrush(QBrush(gradient));
-                painter.drawRoundedRect(QRectF(topright0, topright1), 0.0, 0.0);
-
-                // Widget
-                painter.setBrush(QBrush("#FFFFFF"));
-                painter.setRenderHint(QPainter::Antialiasing);
-                painter.drawRoundedRect(
-                  QRectF(QPointF(margin, margin), QPointF(width - margin, height - margin)),
-                  radius,
-                  radius);
-        }
+        // Widget
+        painter.setBrush(QBrush("#FFFFFF"));
+        painter.setRenderHint(QPainter::Antialiasing);
+        painter.drawRoundedRect(
+          QRectF(QPointF(margin, margin), QPointF(width - margin, height - margin)),
+          radius,
+          radius);
+}
diff --git a/src/ui/TextField.cpp b/src/ui/TextField.cpp
index c45820858cbdf1e5e403bbf8392468ed7ee6cdf1..0ae2516d7892e60667e84ce051904eea706642b7 100644
--- a/src/ui/TextField.cpp
+++ b/src/ui/TextField.cpp
@@ -1,6 +1,6 @@
 #include "TextField.h"
 
-#include <QApplication>
+#include <QCoreApplication>
 #include <QEventTransition>
 #include <QFontDatabase>
 #include <QPaintEvent>
diff --git a/src/ui/ToggleButton.cpp b/src/ui/ToggleButton.cpp
index 755f528ffa8c7e0a55b868ca53d5d9625468e0ca..f94114891ffbd70de22dde22a97eba562c792787 100644
--- a/src/ui/ToggleButton.cpp
+++ b/src/ui/ToggleButton.cpp
@@ -1,5 +1,5 @@
-#include <QApplication>
 #include <QColor>
+#include <QCoreApplication>
 #include <QEvent>
 #include <QPainter>