diff --git a/src/corelib/kernel/qcore_mac_objc.mm b/src/corelib/kernel/qcore_mac_objc.mm
index 266faca..cf9dafb 100644
--- a/src/corelib/kernel/qcore_mac_objc.mm
+++ b/src/corelib/kernel/qcore_mac_objc.mm
@@ -140,7 +140,8 @@ QMacAutoReleasePool::QMacAutoReleasePool()
 {
     Class trackerClass = [QMacAutoReleasePoolTracker class];
 
-#ifdef QT_DEBUG
+// Patch: Disable this debug code because it is very slow.
+#ifdef QT_DEBUG____REMOVED
     void *poolFrame = nullptr;
     if (__builtin_available(macOS 10.14, iOS 12.0, tvOS 12.0, watchOS 5.0, *)) {
         void *frame;
diff --git a/src/gui/kernel/qstylehints.cpp b/src/gui/kernel/qstylehints.cpp
index 48060a2..fff3271 100644
--- a/src/gui/kernel/qstylehints.cpp
+++ b/src/gui/kernel/qstylehints.cpp
@@ -374,7 +374,11 @@ bool QStyleHints::showIsMaximized() const
 */
 bool QStyleHints::showShortcutsInContextMenus() const
 {
-    return themeableHint(QPlatformTheme::ShowShortcutsInContextMenus, QPlatformIntegration::ShowShortcutsInContextMenus).toBool();
+    // Patch: Always show hotkeys in the standard context menu.
+    // This patch can be removed in 5.13 and later versions.
+    // See: https://bugreports.qt.io/browse/QTBUG-71471
+    return true;
+    // return themeableHint(QPlatformTheme::ShowShortcutsInContextMenus, QPlatformIntegration::ShowShortcutsInContextMenus).toBool();
 }
 
 /*!
diff --git a/src/gui/painting/qbezier.cpp b/src/gui/painting/qbezier.cpp
index 65e6063..fcf19a1 100644
--- a/src/gui/painting/qbezier.cpp
+++ b/src/gui/painting/qbezier.cpp
@@ -400,6 +400,33 @@ static bool addCircle(const QBezier *b, qreal offset, QBezier *o)
     return true;
 }
 
+// Patch: Workaround VS2019 compiler bug, see QTBUG-75280.
+#ifdef Q_OS_WIN
+Q_NEVER_INLINE void QBezier::split(QBezier *firstHalf, QBezier *secondHalf) const
+{
+    Q_ASSERT(firstHalf);
+    Q_ASSERT(secondHalf);
+
+    qreal c = (x2 + x3)*.5;
+    firstHalf->x2 = (x1 + x2)*.5;
+    secondHalf->x3 = (x3 + x4)*.5;
+    firstHalf->x1 = x1;
+    secondHalf->x4 = x4;
+    firstHalf->x3 = (firstHalf->x2 + c)*.5;
+    secondHalf->x2 = (secondHalf->x3 + c)*.5;
+    firstHalf->x4 = secondHalf->x1 = (firstHalf->x3 + secondHalf->x2)*.5;
+
+    c = (y2 + y3)/2;
+    firstHalf->y2 = (y1 + y2)*.5;
+    secondHalf->y3 = (y3 + y4)*.5;
+    firstHalf->y1 = y1;
+    secondHalf->y4 = y4;
+    firstHalf->y3 = (firstHalf->y2 + c)*.5;
+    secondHalf->y2 = (secondHalf->y3 + c)*.5;
+    firstHalf->y4 = secondHalf->y1 = (firstHalf->y3 + secondHalf->y2)*.5;
+}
+#endif // Q_OS_WIN
+
 int QBezier::shifted(QBezier *curveSegments, int maxSegments, qreal offset, float threshold) const
 {
     Q_ASSERT(curveSegments);
diff --git a/src/gui/painting/qbezier_p.h b/src/gui/painting/qbezier_p.h
index f8a91e9..50c60b2 100644
--- a/src/gui/painting/qbezier_p.h
+++ b/src/gui/painting/qbezier_p.h
@@ -222,6 +222,8 @@ inline QPointF QBezier::secondDerivedAt(qreal t) const
                        a * y1 + b * y2 + c * y3 + d * y4);
 }
 
+// Patch: Workaround VS2019 compiler bug, see QTBUG-75280.
+#ifndef Q_OS_WIN
 inline void QBezier::split(QBezier *firstHalf, QBezier *secondHalf) const
 {
     Q_ASSERT(firstHalf);
@@ -245,6 +247,7 @@ inline void QBezier::split(QBezier *firstHalf, QBezier *secondHalf) const
     secondHalf->y2 = (secondHalf->y3 + c)*.5;
     firstHalf->y4 = secondHalf->y1 = (firstHalf->y3 + secondHalf->y2)*.5;
 }
+#endif // Q_OS_WIN
 
 inline void QBezier::parameterSplitLeft(qreal t, QBezier *left)
 {
diff --git a/src/gui/painting/qpainter.cpp b/src/gui/painting/qpainter.cpp
index b70b29e..9519894 100644
--- a/src/gui/painting/qpainter.cpp
+++ b/src/gui/painting/qpainter.cpp
@@ -6245,6 +6245,91 @@ static QPixmap generateWavyPixmap(qreal maxRadius, const QPen &pen)
     return pixmap;
 }
 
+// Patch: Improved underline with SpellCheck style for macOS and Windows.
+// Added implementation of underline drawing from Chrome.
+static QPixmap generateChromeSpellcheckPixmap(qreal descent, qreal factor, const QPen &pen) {
+    QString key = QLatin1String("ChromeUnderline-")
+        % pen.color().name()
+        % HexString<qreal>(factor)
+        % HexString<qreal>(pen.widthF());
+
+    QPixmap pixmap;
+    if (QPixmapCache::find(key, pixmap)) {
+        return pixmap;
+    }
+    // https://chromium.googlesource.com/chromium/src/+/refs/heads/master/third_party/blink/renderer/core/paint/document_marker_painter.cc
+
+#ifdef Q_OS_MAC
+
+    constexpr qreal kMarkerHeight = 3;
+
+    const qreal height = kMarkerHeight * factor;
+    const qreal width = height * 2;
+
+    pixmap = QPixmap(qCeil(width), qFloor(height) * 2);
+    pixmap.setDevicePixelRatio(qApp->devicePixelRatio());
+    pixmap.fill(Qt::transparent);
+    {
+        QPainter imgPainter(&pixmap);
+        imgPainter.setPen(Qt::NoPen);
+        imgPainter.setBrush(pen.color());
+        imgPainter.setRenderHints(
+            QPainter::Antialiasing | QPainter::SmoothPixmapTransform);
+        imgPainter.drawEllipse(0, 0, qFloor(height), qFloor(height));
+    }
+
+#else
+
+    constexpr qreal kMarkerWidth = 4;
+    constexpr qreal kMarkerHeight = 2;
+
+    const auto x1 = (kMarkerWidth * -3 / 8) * factor;
+    const auto y1 = (kMarkerHeight * 3 / 4) * factor;
+
+    const auto cY = (kMarkerHeight * 1 / 4) * factor;
+
+    const auto c1X1 = (kMarkerWidth * -1 / 8) * factor;
+    const auto c1X2 = (kMarkerWidth * 3 / 8) * factor;
+    const auto c1X3 = (kMarkerWidth * 7 / 8) * factor;
+
+    const auto c2X1 = (kMarkerWidth * 1 / 8) * factor;
+    const auto c2X2 = (kMarkerWidth * 5 / 8) * factor;
+    const auto c2X3 = (kMarkerWidth * 9 / 8) * factor;
+
+    QPainterPath path;
+    path.moveTo(x1, y1);
+    path.cubicTo(c1X1, y1,
+        c1X1, cY,
+        c2X1, cY);
+    path.cubicTo(c1X2, cY,
+        c1X2, y1,
+        c2X2, y1);
+    path.cubicTo(c1X3, y1,
+        c1X3, cY,
+        c2X3, cY);
+
+    pixmap = QPixmap(kMarkerWidth * factor, kMarkerHeight * factor * 2);
+    pixmap.fill(Qt::transparent);
+    {
+        QPen wavePen = pen;
+        wavePen.setCapStyle(Qt::RoundCap);
+        wavePen.setJoinStyle(Qt::RoundJoin);
+        wavePen.setWidthF(1 * factor);
+
+        QPainter imgPainter(&pixmap);
+        imgPainter.setPen(std::move(wavePen));
+        imgPainter.setRenderHint(QPainter::Antialiasing);
+        imgPainter.translate(0, descent - (kMarkerHeight * factor));
+        imgPainter.drawPath(std::move(path));
+    }
+
+#endif
+
+    QPixmapCache::insert(std::move(key), pixmap);
+
+    return pixmap;
+}
+
 static void drawTextItemDecoration(QPainter *painter, const QPointF &pos, const QFontEngine *fe, QTextEngine *textEngine,
                                    QTextCharFormat::UnderlineStyle underlineStyle,
                                    QTextItem::RenderFlags flags, qreal width,
@@ -6262,7 +6347,9 @@ static void drawTextItemDecoration(QPainter *painter, const QPointF &pos, const
     pen.setWidthF(fe->lineThickness().toReal());
     pen.setCapStyle(Qt::FlatCap);
 
-    QLineF line(qFloor(pos.x()), pos.y(), qFloor(pos.x() + width), pos.y());
+    // Patch: Improved underline with SpellCheck style for macOS and Windows.
+    // Slightly move the beginning of the underline to the right.
+    QLineF line(qFloor(pos.x() + 1), pos.y(), qFloor(pos.x() + width), pos.y());
 
     bool wasCompatiblePainting = painter->renderHints()
             & QPainter::Qt4CompatiblePainting;
@@ -6273,13 +6360,29 @@ static void drawTextItemDecoration(QPainter *painter, const QPointF &pos, const
     const qreal underlineOffset = fe->underlinePosition().toReal();
 
     if (underlineStyle == QTextCharFormat::SpellCheckUnderline) {
-        QPlatformTheme *theme = QGuiApplicationPrivate::platformTheme();
-        if (theme)
-            underlineStyle = QTextCharFormat::UnderlineStyle(theme->themeHint(QPlatformTheme::SpellCheckUnderlineStyle).toInt());
-        if (underlineStyle == QTextCharFormat::SpellCheckUnderline) // still not resolved
-            underlineStyle = QTextCharFormat::WaveUnderline;
-    }
+        const qreal fontFactor = qreal(charFormat.font().pixelSize()) / qreal(10.);
+        painter->save();
+        painter->translate(0, pos.y() + 1);
+        const qreal maxHeight = fe->descent().toReal() - qreal(1);
+
+        QColor uc = charFormat.underlineColor();
+        if (uc.isValid())
+            pen.setColor(uc);
 
+        const QPixmap wave = generateChromeSpellcheckPixmap(maxHeight, fontFactor, pen);
+        const int descent = qFloor(maxHeight);
+
+        painter->setBrushOrigin(painter->brushOrigin().x(), 0);
+#ifdef Q_OS_MAC
+        const auto h = wave.height() / 2;
+        painter->drawTiledPixmap(
+            QRectF(pos.x(), (descent - h) / 2., qCeil(width), h),
+            wave);
+#else
+        painter->fillRect(pos.x(), 0, qCeil(width), descent, wave);
+#endif
+        painter->restore();
+    } else
     if (underlineStyle == QTextCharFormat::WaveUnderline) {
         painter->save();
         painter->translate(0, pos.y() + 1);
diff --git a/src/gui/text/qinputcontrol.cpp b/src/gui/text/qinputcontrol.cpp
index 3381fdb..6036f05 100644
--- a/src/gui/text/qinputcontrol.cpp
+++ b/src/gui/text/qinputcontrol.cpp
@@ -40,6 +40,10 @@
 #include "qinputcontrol_p.h"
 #include <QtGui/qevent.h>
 
+// Patch: Enable Ctrl+key and Ctrl+Shift+key in all locales except German.
+// See https://github.com/telegramdesktop/tdesktop/pull/1185.
+#include <QtCore/QLocale>
+
 QT_BEGIN_NAMESPACE
 
 QInputControl::QInputControl(Type type, QObject *parent)
@@ -67,9 +71,16 @@ bool QInputControl::isAcceptableInput(const QKeyEvent *event) const
     if (c.category() == QChar::Other_Format)
         return true;
 
-    // QTBUG-35734: ignore Ctrl/Ctrl+Shift; accept only AltGr (Alt+Ctrl) on German keyboards
-    if (event->modifiers() == Qt::ControlModifier
-            || event->modifiers() == (Qt::ShiftModifier | Qt::ControlModifier)) {
+    // Patch: Enable Ctrl+key and Ctrl+Shift+key in all locales except German.
+    // See https://github.com/telegramdesktop/tdesktop/pull/1185.
+    bool skipCtrlAndCtrlShift = false;
+    if (QGuiApplication::inputMethod()->locale().language() == QLocale::German) {
+        if (event->modifiers() == Qt::ControlModifier
+            || event->modifiers() == (Qt::ControlModifier | Qt::ShiftModifier)) {
+            skipCtrlAndCtrlShift = true;
+        }
+    }
+    if (skipCtrlAndCtrlShift) {
         return false;
     }
 
diff --git a/src/gui/text/qtextengine.cpp b/src/gui/text/qtextengine.cpp
index a783458..9a1fe9f 100644
--- a/src/gui/text/qtextengine.cpp
+++ b/src/gui/text/qtextengine.cpp
@@ -3028,7 +3028,8 @@ bool QTextEngine::atWordSeparator(int position) const
     case '&':
     case '^':
     case '*':
-    case '\'':
+    // Patch: Make the apostrophe a non-separator for words.
+    //case '\'':
     case '"':
     case '`':
     case '~':
diff --git a/src/gui/text/qtextcursor.cpp b/src/gui/text/qtextcursor.cpp
index c88497840f..2b08d13834 100644
--- a/src/gui/text/qtextcursor.cpp
+++ b/src/gui/text/qtextcursor.cpp
@@ -510,14 +510,16 @@ bool QTextCursorPrivate::movePosition(QTextCursor::MoveOperation op, QTextCursor
         const int len = blockIt.length() - 1;
         if (relativePos >= len)
             return false;
-        if (engine->atWordSeparator(relativePos)) {
-            ++relativePos;
-            while (relativePos < len && engine->atWordSeparator(relativePos))
-                ++relativePos;
-        } else {
-            while (relativePos < len && !attributes[relativePos].whiteSpace && !engine->atWordSeparator(relativePos))
-                ++relativePos;
-        }
+        // Patch: Improved apostrophe processing.
+        relativePos = engine->toEdge(relativePos, len, true);
+        // if (engine->atWordSeparator(relativePos)) {
+        //     ++relativePos;
+        //     while (relativePos < len && engine->atWordSeparator(relativePos))
+        //         ++relativePos;
+        // } else {
+        //     while (relativePos < len && !attributes[relativePos].whiteSpace && !engine->atWordSeparator(relativePos))
+        //         ++relativePos;
+        // }
         newPosition = blockIt.position() + relativePos;
         break;
     }
diff --git a/src/gui/text/qtextengine.cpp b/src/gui/text/qtextengine.cpp
index a7834587b1..a89dfe228c 100644
--- a/src/gui/text/qtextengine.cpp
+++ b/src/gui/text/qtextengine.cpp
@@ -3041,6 +3041,74 @@ bool QTextEngine::atWordSeparator(int position) const
     return false;
 }
 
+// Patch: Improved apostrophe processing.
+// We should consider apostrophes as word separators when there is more than
+// one apostrophe in a row, or when the apostrophe is at the beginning or end
+// of the word.
+int QTextEngine::toEdge(int pos, int len, bool isRightDirection) {
+    const auto step = isRightDirection ? 1 : -1;
+    const auto next = isRightDirection ? 0 : -1;
+
+    QCharAttributes *attributes = const_cast<QCharAttributes *>(this->attributes());
+
+    const auto atApostrophe = [&](int position) {
+        return layoutData->string.at(position).unicode() == '\'';
+    };
+
+    const auto atSepOrApost = [&](int position) {
+        return atApostrophe(position) || atWordSeparator(position);
+    };
+
+    const auto inBounds = [&](int position) {
+        return isRightDirection
+            ? position < len
+            : position > 0;
+    };
+
+    const auto atSepOrSpace = [&](int position) {
+        return attributes[position].whiteSpace || atWordSeparator(position);
+    };
+
+    const auto isApostropheInWord = [&](int position) {
+        if (!atApostrophe(position)) {
+            return false;
+        }
+        auto p = position - 1;
+        if (p <= 0 || atSepOrSpace(p)) {
+            return false;
+        }
+        p = position + 1;
+        if (p >= len || atSepOrSpace(p)) {
+            return false;
+        }
+        return true;
+    };
+
+    auto counter = 0;
+    while (inBounds(pos) && atSepOrApost(pos + next)) {
+        counter++;
+        pos += step;
+    }
+    // If it's not the single apostrophe, then that's non-letter part of text.
+    if (counter > 1 || (counter == 1 && !isApostropheInWord(pos - step + next))) {
+        return pos;
+    }
+
+    bool isPrevApostrophe = false;
+    while (inBounds(pos) && !atSepOrSpace(pos + next)) {
+        bool isNextApostrophe = atApostrophe(pos + next);
+        if (isPrevApostrophe && isNextApostrophe) {
+            break;
+        }
+        pos += step;
+        isPrevApostrophe = isNextApostrophe;
+    }
+    if (isPrevApostrophe) {
+        pos += -step;
+    }
+    return pos;
+}
+
 void QTextEngine::setPreeditArea(int position, const QString &preeditText)
 {
     if (preeditText.isEmpty()) {
diff --git a/src/gui/text/qtextengine_p.h b/src/gui/text/qtextengine_p.h
index e9187ea605..51997ba066 100644
--- a/src/gui/text/qtextengine_p.h
+++ b/src/gui/text/qtextengine_p.h
@@ -622,6 +622,8 @@ private:
 
 public:
     bool atWordSeparator(int position) const;
+    // Patch: Improved apostrophe processing.
+    int toEdge(int pos, int len, bool isRightDirection);
 
     QString elidedText(Qt::TextElideMode mode, const QFixed &width, int flags = 0, int from = 0, int count = -1) const;
 
diff --git a/src/gui/text/qtextlayout.cpp b/src/gui/text/qtextlayout.cpp
index f3f0caa379..081c5f03c0 100644
--- a/src/gui/text/qtextlayout.cpp
+++ b/src/gui/text/qtextlayout.cpp
@@ -706,16 +706,22 @@ int QTextLayout::nextCursorPosition(int oldPos, CursorMode mode) const
         while (oldPos < len && !attributes[oldPos].graphemeBoundary)
             oldPos++;
     } else {
-        if (oldPos < len && d->atWordSeparator(oldPos)) {
-            oldPos++;
-            while (oldPos < len && d->atWordSeparator(oldPos))
-                oldPos++;
-        } else {
-            while (oldPos < len && !attributes[oldPos].whiteSpace && !d->atWordSeparator(oldPos))
-                oldPos++;
-        }
+        // Patch: Skip to the end of the current word, not to the start of the next one.
         while (oldPos < len && attributes[oldPos].whiteSpace)
             oldPos++;
+        // Patch: Improved apostrophe processing.
+        oldPos = d->toEdge(oldPos, len, true);
+        // if (oldPos < len && d->atWordSeparator(oldPos)) {
+        //     oldPos++;
+        //     while (oldPos < len && d->atWordSeparator(oldPos))
+        //         oldPos++;
+        // } else {
+        //     while (oldPos < len && !attributes[oldPos].whiteSpace && !d->atWordSeparator(oldPos))
+        //         oldPos++;
+        // }
+        // Patch: Skip to the end of the current word, not to the start of the next one.
+        //while (oldPos < len && attributes[oldPos].whiteSpace)
+        //    oldPos++;
     }
 
     return oldPos;
@@ -745,14 +751,16 @@ int QTextLayout::previousCursorPosition(int oldPos, CursorMode mode) const
         while (oldPos > 0 && attributes[oldPos - 1].whiteSpace)
             oldPos--;
 
-        if (oldPos && d->atWordSeparator(oldPos-1)) {
-            oldPos--;
-            while (oldPos && d->atWordSeparator(oldPos-1))
-                oldPos--;
-        } else {
-            while (oldPos > 0 && !attributes[oldPos - 1].whiteSpace && !d->atWordSeparator(oldPos-1))
-                oldPos--;
-        }
+        // Patch: Improved apostrophe processing.
+        oldPos = d->toEdge(oldPos, len, false);
+        // if (oldPos && d->atWordSeparator(oldPos-1)) {
+        //     oldPos--;
+        //     while (oldPos && d->atWordSeparator(oldPos-1))
+        //         oldPos--;
+        // } else {
+        //     while (oldPos > 0 && !attributes[oldPos - 1].whiteSpace && !d->atWordSeparator(oldPos-1))
+        //         oldPos--;
+        // }
     }
 
     return oldPos;
diff --git a/src/platformsupport/linuxaccessibility/constant_mappings.cpp b/src/platformsupport/linuxaccessibility/constant_mappings.cpp
index fce2919..4a7d0f7 100644
--- a/src/platformsupport/linuxaccessibility/constant_mappings.cpp
+++ b/src/platformsupport/linuxaccessibility/constant_mappings.cpp
@@ -79,7 +79,12 @@ quint64 spiStatesFromQState(QAccessible::State state)
     if (state.checkStateMixed)
         setSpiStateBit(&spiState, ATSPI_STATE_INDETERMINATE);
     if (state.readOnly)
+// Patch: Support build with AT-SPI version below 2.16.
+#ifdef ATSPI_STATE_READ_ONLY
         setSpiStateBit(&spiState, ATSPI_STATE_READ_ONLY);
+#else // ATSPI_STATE_READ_ONLY
+        unsetSpiStateBit(&spiState, ATSPI_STATE_EDITABLE);
+#endif // ATSPI_STATE_READ_ONLY
     //        if (state.HotTracked)
     if (state.defaultButton)
         setSpiStateBit(&spiState, ATSPI_STATE_IS_DEFAULT);
diff --git a/src/plugins/platforminputcontexts/compose/qcomposeplatforminputcontext.cpp b/src/plugins/platforminputcontexts/compose/qcomposeplatforminputcontext.cpp
index 81a7302..42bab9a 100644
--- a/src/plugins/platforminputcontexts/compose/qcomposeplatforminputcontext.cpp
+++ b/src/plugins/platforminputcontexts/compose/qcomposeplatforminputcontext.cpp
@@ -273,6 +273,12 @@ bool QComposeInputContext::checkComposeTable()
 
 void QComposeInputContext::commitText(uint character) const
 {
+    // Patch: Crash fix when not focused widget still receives input events.
+    if (!m_focusObject) {
+        qWarning("QComposeInputContext::commitText: m_focusObject == nullptr, cannot commit text");
+        return;
+    }
+
     QInputMethodEvent event;
     event.setCommitString(QChar(character));
     QCoreApplication::sendEvent(m_focusObject, &event);
diff --git a/src/plugins/platforminputcontexts/platforminputcontexts.pro b/src/plugins/platforminputcontexts/platforminputcontexts.pro
index ed6b1b8..d17c6ba 100644
--- a/src/plugins/platforminputcontexts/platforminputcontexts.pro
+++ b/src/plugins/platforminputcontexts/platforminputcontexts.pro
@@ -2,7 +2,8 @@ TEMPLATE = subdirs
 QT_FOR_CONFIG += gui-private
 
 qtHaveModule(dbus) {
-!mac:!win32:SUBDIRS += ibus
+# Patch: Adding fcitx/hime/nimf input context plugin to our static build.
+!mac:!win32:SUBDIRS += ibus fcitx hime nimf
 }
 
 qtConfig(xcb): SUBDIRS += compose
diff --git a/src/plugins/platforms/cocoa/qcocoaapplicationdelegate.mm b/src/plugins/platforms/cocoa/qcocoaapplicationdelegate.mm
index 2cf6672..ef25bb4 100644
--- a/src/plugins/platforms/cocoa/qcocoaapplicationdelegate.mm
+++ b/src/plugins/platforms/cocoa/qcocoaapplicationdelegate.mm
@@ -175,7 +175,8 @@ QT_USE_NAMESPACE
     if (reflectionDelegate) {
         if ([reflectionDelegate respondsToSelector:@selector(applicationShouldTerminate:)])
             return [reflectionDelegate applicationShouldTerminate:sender];
-        return NSTerminateNow;
+        // Patch: Don't terminate if reflectionDelegate does not respond to that selector, just use the default.
+        //return NSTerminateNow;
     }
 
     if ([self canQuit]) {
@@ -252,7 +253,11 @@ QT_USE_NAMESPACE
 
 - (void)applicationDidFinishLaunching:(NSNotification *)aNotification
 {
-    Q_UNUSED(aNotification);
+    // Patch: We need to catch that notification in delegate.
+    if (reflectionDelegate
+        && [reflectionDelegate respondsToSelector:@selector(applicationDidFinishLaunching:)])
+        [reflectionDelegate applicationDidFinishLaunching:aNotification];
+
     inLaunch = false;
 
     if (qEnvironmentVariableIsEmpty("QT_MAC_DISABLE_FOREGROUND_APPLICATION_TRANSFORM")) {
diff --git a/src/plugins/platforms/cocoa/qcocoakeymapper.mm b/src/plugins/platforms/cocoa/qcocoakeymapper.mm
index 350ae4b..457bb34 100644
--- a/src/plugins/platforms/cocoa/qcocoakeymapper.mm
+++ b/src/plugins/platforms/cocoa/qcocoakeymapper.mm
@@ -462,7 +462,8 @@ QList<int> QCocoaKeyMapper::possibleKeys(const QKeyEvent *event) const
         Qt::KeyboardModifiers neededMods = ModsTbl[i];
         int key = kbItem->qtKey[i];
         if (key && key != baseKey && ((keyMods & neededMods) == neededMods)) {
-            ret << int(key + (keyMods & ~neededMods));
+            // Patch: Fix non-english layout global shortcuts.
+            ret << int(key + neededMods);
         }
     }
     return ret;
diff --git a/src/plugins/platforms/cocoa/qcocoasystemtrayicon.mm b/src/plugins/platforms/cocoa/qcocoasystemtrayicon.mm
index 597cfa8..579d797 100644
--- a/src/plugins/platforms/cocoa/qcocoasystemtrayicon.mm
+++ b/src/plugins/platforms/cocoa/qcocoasystemtrayicon.mm
@@ -96,12 +96,17 @@ QT_USE_NAMESPACE
 
 @interface QT_MANGLE_NAMESPACE(QNSStatusItem) : NSObject <NSUserNotificationCenterDelegate>
 @property (nonatomic, assign) QCocoaMenu *menu;
+// Patch: Create a rich os x tray icon (pixel-perfect, theme switching).
+@property (nonatomic, assign) bool menuVisible;
+@property (nonatomic, readonly) bool iconSelected;
 @property (nonatomic, assign) QIcon icon;
 @property (nonatomic, readonly) NSStatusItem *item;
 @property (nonatomic, readonly) QRectF geometry;
 - (instancetype)initWithSysTray:(QCocoaSystemTrayIcon *)systray;
 - (void)triggerSelector:(id)sender button:(Qt::MouseButton)mouseButton;
 - (void)doubleClickSelector:(id)sender;
+- (void)setIconSelected:(bool)selected;
+- (bool)hasMenu;
 @end
 
 @interface QT_MANGLE_NAMESPACE(QNSImageView) : NSImageView
@@ -173,7 +178,10 @@ void QCocoaSystemTrayIcon::updateIcon(const QIcon &icon)
     // (device independent pixels). The menu height on past and
     // current OS X versions is 22 points. Provide some future-proofing
     // by deriving the icon height from the menu height.
-    const int padding = 4;
+
+    // Patch: Create a rich os x tray icon (pixel-perfect, theme switching).
+    const int padding = 0;
+
     const int menuHeight = [[NSStatusBar systemStatusBar] thickness];
     const int maxImageHeight = menuHeight - padding;
 
@@ -183,8 +191,12 @@ void QCocoaSystemTrayIcon::updateIcon(const QIcon &icon)
     // devicePixelRatio for the "best" screen on the system.
     qreal devicePixelRatio = qApp->devicePixelRatio();
     const int maxPixmapHeight = maxImageHeight * devicePixelRatio;
+
+    // Patch: Create a rich os x tray icon (pixel-perfect, theme switching).
+    const QIcon::Mode mode = m_sys->item.iconSelected ? QIcon::Selected : QIcon::Normal;
+
     QSize selectedSize;
-    Q_FOREACH (const QSize& size, sortByHeight(icon.availableSizes())) {
+    Q_FOREACH (const QSize& size, sortByHeight(icon.availableSizes(mode))) {
         // Select a pixmap based on the height. We want the largest pixmap
         // with a height smaller or equal to maxPixmapHeight. The pixmap
         // may rectangular; assume it has a reasonable size. If there is
@@ -200,9 +212,9 @@ void QCocoaSystemTrayIcon::updateIcon(const QIcon &icon)
 
     // Handle SVG icons, which do not return anything for availableSizes().
     if (!selectedSize.isValid())
-        selectedSize = icon.actualSize(QSize(maxPixmapHeight, maxPixmapHeight));
+        selectedSize = icon.actualSize(QSize(maxPixmapHeight, maxPixmapHeight), mode);
 
-    QPixmap pixmap = icon.pixmap(selectedSize);
+    QPixmap pixmap = icon.pixmap(selectedSize, mode);
 
     // Draw a low-resolution icon if there is not enough pixels for a retina
     // icon. This prevents showing a small icon on retina displays.
@@ -301,6 +313,10 @@ QT_END_NAMESPACE
 {
     self.down = NO;
 
+    // Patch: Create a rich os x tray icon (pixel-perfect, theme switching).
+    [self.parent setIconSelected:false];
+    self.parent.menuVisible = false;
+
     [self setNeedsDisplay:YES];
 }
 
@@ -310,6 +326,9 @@ QT_END_NAMESPACE
     int clickCount = [mouseEvent clickCount];
     [self setNeedsDisplay:YES];
 
+    // Patch: Create a rich os x tray icon (pixel-perfect, theme switching).
+    [self.parent setIconSelected:((clickCount != 2) && [self.parent hasMenu])];
+
     if (clickCount == 2) {
         [self menuTrackingDone:nil];
         [self.parent doubleClickSelector:self];
@@ -326,6 +345,10 @@ QT_END_NAMESPACE
 - (void)mouseUp:(NSEvent *)mouseEvent
 {
     Q_UNUSED(mouseEvent);
+
+    // Patch: Create a rich os x tray icon (pixel-perfect, theme switching).
+    [self.parent setIconSelected:false];
+
     [self menuTrackingDone:nil];
 }
 
@@ -337,6 +360,10 @@ QT_END_NAMESPACE
 - (void)rightMouseUp:(NSEvent *)mouseEvent
 {
     Q_UNUSED(mouseEvent);
+
+    // Patch: Create a rich os x tray icon (pixel-perfect, theme switching).
+    [self.parent setIconSelected:false];
+
     [self menuTrackingDone:nil];
 }
 
@@ -352,7 +379,8 @@ QT_END_NAMESPACE
 }
 
 - (void)drawRect:(NSRect)rect {
-    [[self.parent item] drawStatusBarBackgroundInRect:rect withHighlight:self.down];
+    // Patch: Create a rich os x tray icon (pixel-perfect, theme switching).
+    [[self.parent item] drawStatusBarBackgroundInRect:rect withHighlight:([self.parent hasMenu] && self.down)];
     [super drawRect:rect];
 }
 @end
@@ -372,6 +400,10 @@ QT_END_NAMESPACE
     if (self) {
         item = [[[NSStatusBar systemStatusBar] statusItemWithLength:NSSquareStatusItemLength] retain];
         menu = nullptr;
+
+        // Patch: Create a rich os x tray icon (pixel-perfect, theme switching).
+        self.menuVisible = false;
+
         systray = sys;
         imageCell = [[QNSImageView alloc] initWithParent:self];
         [item setView: imageCell];
@@ -382,6 +414,11 @@ QT_END_NAMESPACE
 - (void)dealloc {
     [[NSStatusBar systemStatusBar] removeStatusItem:item];
     [[NSNotificationCenter defaultCenter] removeObserver:imageCell];
+
+    // Patch: Fix crash in macOS 10.14.
+    // Somehow item and imageCell are retained and attempt to be drawn if left in view.
+    [item setView: nil];
+
     imageCell.parent = nil;
     [imageCell release];
     [item release];
@@ -416,6 +453,10 @@ QT_END_NAMESPACE
          selector:@selector(menuTrackingDone:)
              name:NSMenuDidEndTrackingNotification
                  object:m];
+
+        // Patch: Create a rich os x tray icon (pixel-perfect, theme switching).
+        self.menuVisible = true;
+
         [item popUpStatusItemMenu: m];
     }
 }
@@ -427,6 +468,15 @@ QT_END_NAMESPACE
     emit systray->activated(QPlatformSystemTrayIcon::DoubleClick);
 }
 
+- (void)setIconSelected:(bool)selected {
+    _iconSelected = selected;
+    systray->updateIcon(icon);
+}
+
+- (bool)hasMenu {
+    return menu != nil;
+}
+
 - (BOOL)userNotificationCenter:(NSUserNotificationCenter *)center shouldPresentNotification:(NSUserNotification *)notification {
     Q_UNUSED(center);
     Q_UNUSED(notification);
diff --git a/src/plugins/platforms/cocoa/qnsview_keys.mm b/src/plugins/platforms/cocoa/qnsview_keys.mm
index ad75127..9a9d196 100644
--- a/src/plugins/platforms/cocoa/qnsview_keys.mm
+++ b/src/plugins/platforms/cocoa/qnsview_keys.mm
@@ -86,21 +86,29 @@
     quint32 nativeVirtualKey = [nsevent keyCode];
 
     QChar ch = QChar::ReplacementCharacter;
-    int keyCode = Qt::Key_unknown;
-
-    // If a dead key occurs as a result of pressing a key combination then
-    // characters will have 0 length, but charactersIgnoringModifiers will
-    // have a valid character in it. This enables key combinations such as
-    // ALT+E to be used as a shortcut with an English keyboard even though
-    // pressing ALT+E will give a dead key while doing normal text input.
-    if ([characters length] != 0 || [charactersIgnoringModifiers length] != 0) {
-        auto ctrlOrMetaModifier = qApp->testAttribute(Qt::AA_MacDontSwapCtrlAndMeta) ? Qt::ControlModifier : Qt::MetaModifier;
-        if (((modifiers & ctrlOrMetaModifier) || (modifiers & Qt::AltModifier)) && ([charactersIgnoringModifiers length] != 0))
-            ch = QChar([charactersIgnoringModifiers characterAtIndex:0]);
-        else if ([characters length] != 0)
-            ch = QChar([characters characterAtIndex:0]);
-        keyCode = [self convertKeyCode:ch];
-    }
+
+    // Patch: Fix Alt+.. shortcuts in OS X. See https://bugreports.qt.io/browse/QTBUG-42584 at the end.
+    if ([characters length] != 0)
+        ch = QChar([characters characterAtIndex:0]);
+    else if ([charactersIgnoringModifiers length] != 0 && ((modifiers & Qt::MetaModifier) || (modifiers & Qt::AltModifier)))
+        ch = QChar([charactersIgnoringModifiers characterAtIndex:0]);
+
+    int keyCode = [self convertKeyCode:ch];
+    // int keyCode = Qt::Key_unknown;
+
+    // // If a dead key occurs as a result of pressing a key combination then
+    // // characters will have 0 length, but charactersIgnoringModifiers will
+    // // have a valid character in it. This enables key combinations such as
+    // // ALT+E to be used as a shortcut with an English keyboard even though
+    // // pressing ALT+E will give a dead key while doing normal text input.
+    // if ([characters length] != 0 || [charactersIgnoringModifiers length] != 0) {
+    //     auto ctrlOrMetaModifier = qApp->testAttribute(Qt::AA_MacDontSwapCtrlAndMeta) ? Qt::ControlModifier : Qt::MetaModifier;
+    //     if (((modifiers & ctrlOrMetaModifier) || (modifiers & Qt::AltModifier)) && ([charactersIgnoringModifiers length] != 0))
+    //         ch = QChar([charactersIgnoringModifiers characterAtIndex:0]);
+    //     else if ([characters length] != 0)
+    //         ch = QChar([characters characterAtIndex:0]);
+    //     keyCode = [self convertKeyCode:ch];
+    // }
 
     // we will send a key event unless the input method sets m_sendKeyEvent to false
     m_sendKeyEvent = true;
@@ -196,6 +204,23 @@
         [super keyUp:nsevent];
 }
 
+// Patch: Enable Ctrl+Tab and Ctrl+Shift+Tab / Ctrl+Backtab handle in-app.
+- (BOOL)performKeyEquivalent:(NSEvent *)nsevent
+{
+    NSString *chars = [nsevent charactersIgnoringModifiers];
+
+    if ([nsevent type] == NSKeyDown && [chars length] > 0) {
+        QChar ch = [chars characterAtIndex:0];
+        Qt::Key qtKey = qt_mac_cocoaKey2QtKey(ch);
+        if ([nsevent modifierFlags] & NSControlKeyMask
+                && (qtKey == Qt::Key_Tab || qtKey == Qt::Key_Backtab)) {
+            [self handleKeyEvent:nsevent eventType:int(QEvent::KeyPress)];
+            return YES;
+        }
+    }
+    return [super performKeyEquivalent:nsevent];
+}
+
 - (void)cancelOperation:(id)sender
 {
     Q_UNUSED(sender);
diff --git a/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp b/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp
index 9de3268..8b281c9 100644
--- a/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp
+++ b/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp
@@ -1179,7 +1179,14 @@ void QWindowsNativeFileDialogBase::selectFile(const QString &fileName) const
     // Hack to prevent CLSIDs from being set as file name due to
     // QFileDialogPrivate::initialSelection() being QString-based.
     if (!isClsid(fileName))
-        m_fileDialog->SetFileName((wchar_t*)fileName.utf16());
+    // Patch: Fix handle of full fileName.
+    {
+        QString file = QDir::toNativeSeparators(fileName);
+        int lastBackSlash = file.lastIndexOf(QChar::fromLatin1('\\'));
+        if (lastBackSlash >= 0)
+            file = file.mid(lastBackSlash + 1);
+        m_fileDialog->SetFileName((wchar_t*)file.utf16());;
+    }
 }
 
 // Return the index of the selected filter, accounting for QFileDialog
@@ -1456,7 +1463,8 @@ static QString createTemporaryItemCopy(QWindowsShellItem &qItem, QString *errorM
 static QUrl itemToDialogUrl(QWindowsShellItem &qItem, QString *errorMessage)
 {
     QUrl url = qItem.url();
-    if (url.isLocalFile() || url.scheme().startsWith(QLatin1String("http")))
+    // Patch: Make loaded 'http' resources copy.
+    if (url.isLocalFile()/*|| url.scheme().startsWith(QLatin1String("http"))*/)
         return url;
     const QString path = qItem.path();
     if (path.isEmpty() && !qItem.isDir() && qItem.canStream()) {
diff --git a/src/plugins/platforms/windows/qwindowsservices.cpp b/src/plugins/platforms/windows/qwindowsservices.cpp
index 9504513..811f3d6 100644
--- a/src/plugins/platforms/windows/qwindowsservices.cpp
+++ b/src/plugins/platforms/windows/qwindowsservices.cpp
@@ -125,6 +125,10 @@ static inline bool launchMail(const QUrl &url)
             command.prepend(doubleQuote);
         }
     }
+
+    // Patch: Fix mail launch if no param is expected in this command.
+    if (command.indexOf(QStringLiteral("%1")) < 0) return false;
+
     // Pass the url as the parameter. Should use QProcess::startDetached(),
     // but that cannot handle a Windows command line [yet].
     command.replace(QLatin1String("%1"), url.toString(QUrl::FullyEncoded));
diff --git a/src/plugins/platforms/windows/qwindowswindow.cpp b/src/plugins/platforms/windows/qwindowswindow.cpp
index 7d511bf..da3879c 100644
--- a/src/plugins/platforms/windows/qwindowswindow.cpp
+++ b/src/plugins/platforms/windows/qwindowswindow.cpp
@@ -1351,7 +1351,8 @@ void QWindowsWindow::destroyWindow()
         for (QWindow *w : tlw) {
             if (w->transientParent() == window()) {
                 if (QWindowsWindow *tw = QWindowsWindow::windowsWindowOf(w))
-                    tw->updateTransientParent();
+                    // Patch: Fix possibility of add / remove taskbar icon of the window.
+                    tw->clearTransientParent();
             }
         }
         QWindowsContext *context = QWindowsContext::instance();
@@ -1579,6 +1580,19 @@ void QWindowsWindow::updateTransientParent() const
     // window is found, which can cause issues with modality. Loop up to top level.
     while (newTransientParent && (GetWindowLongPtr(newTransientParent, GWL_STYLE) & WS_CHILD) != 0)
         newTransientParent = GetParent(newTransientParent);
+    // Patch: Fix possibility of add / remove taskbar icon of the window.
+    if (newTransientParent && newTransientParent != oldTransientParent)
+        SetWindowLongPtr(m_data.hwnd, GWL_HWNDPARENT, (LONG_PTR)newTransientParent);
+}
+
+// Patch: Fix possibility of add / remove taskbar icon of the window.
+void QWindowsWindow::clearTransientParent() const
+{
+    if (window()->type() == Qt::Popup)
+        return; // QTBUG-34503, // a popup stays on top, no parent, see also WindowCreationData::fromWindow().
+    // Update transient parent.
+    const HWND oldTransientParent = GetWindow(m_data.hwnd, GW_OWNER);
+    HWND newTransientParent = 0;
 
     if (newTransientParent != oldTransientParent)
         SetWindowLongPtr(m_data.hwnd, GWL_HWNDPARENT, LONG_PTR(newTransientParent));
diff --git a/src/plugins/platforms/windows/qwindowswindow.h b/src/plugins/platforms/windows/qwindowswindow.h
index ce67e46..a60edc1 100644
--- a/src/plugins/platforms/windows/qwindowswindow.h
+++ b/src/plugins/platforms/windows/qwindowswindow.h
@@ -353,6 +353,10 @@ private:
     inline void setWindowState_sys(Qt::WindowStates newState);
     inline void setParent_sys(const QPlatformWindow *parent);
     inline void updateTransientParent() const;
+
+    // Patch: Fix possibility of add / remove taskbar icon of the window.
+    inline void clearTransientParent() const;
+
     void destroyWindow();
     inline bool isDropSiteEnabled() const { return m_dropTarget != 0; }
     void setDropSiteEnabled(bool enabled);
diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp
index bf339ca..4cdf918 100644
--- a/src/widgets/kernel/qwidget.cpp
+++ b/src/widgets/kernel/qwidget.cpp
@@ -5161,6 +5161,17 @@ void QWidget::render(QPainter *painter, const QPoint &targetOffset,
         return; // Fully transparent.
 
     Q_D(QWidget);
+
+    // Patch: save and restore dirtyOpaqueChildren field.
+    //
+    // Just like in QWidget::grab() this field should be restored
+    // after the d->render() call, because it will be set to 1 and
+    // opaqueChildren field will be filled with empty region in
+    // case the widget is hidden (because all the opaque children
+    // will be skipped in isVisible() check).
+    //
+    const bool oldDirtyOpaqueChildren = d->dirtyOpaqueChildren;
+
     const bool inRenderWithPainter = d->extra && d->extra->inRenderWithPainter;
     const QRegion toBePainted = !inRenderWithPainter ? d->prepareToRender(sourceRegion, renderFlags)
                                                      : sourceRegion;
@@ -5182,6 +5193,10 @@ void QWidget::render(QPainter *painter, const QPoint &targetOffset,
     if (!inRenderWithPainter && (opacity < 1.0 || (target->devType() == QInternal::Printer))) {
         d->render_helper(painter, targetOffset, toBePainted, renderFlags);
         d->extra->inRenderWithPainter = inRenderWithPainter;
+
+        // Patch: save and restore dirtyOpaqueChildren field.
+        d->dirtyOpaqueChildren = oldDirtyOpaqueChildren;
+
         return;
     }
 
@@ -5214,6 +5229,9 @@ void QWidget::render(QPainter *painter, const QPoint &targetOffset,
     d->setSharedPainter(oldPainter);
 
     d->extra->inRenderWithPainter = inRenderWithPainter;
+
+    // Patch: save and restore dirtyOpaqueChildren field.
+    d->dirtyOpaqueChildren = oldDirtyOpaqueChildren;
 }
 
 static void sendResizeEvents(QWidget *target)
@@ -8968,7 +8986,8 @@ bool QWidget::event(QEvent *event)
     case QEvent::KeyPress: {
         QKeyEvent *k = (QKeyEvent *)event;
         bool res = false;
-        if (!(k->modifiers() & (Qt::ControlModifier | Qt::AltModifier))) {  //### Add MetaModifier?
+        // Patch: Enable Ctrl+Tab and Ctrl+Shift+Tab / Ctrl+Backtab handle in-app.
+        if (!(k->modifiers() & (Qt::ControlModifier | Qt::AltModifier | Qt::MetaModifier))) {
             if (k->key() == Qt::Key_Backtab
                 || (k->key() == Qt::Key_Tab && (k->modifiers() & Qt::ShiftModifier)))
                 res = focusNextPrevChild(false);
diff --git a/src/widgets/util/qsystemtrayicon_qpa.cpp b/src/widgets/util/qsystemtrayicon_qpa.cpp
index c0bf058..1c8b627 100644
--- a/src/widgets/util/qsystemtrayicon_qpa.cpp
+++ b/src/widgets/util/qsystemtrayicon_qpa.cpp
@@ -93,6 +93,10 @@ void QSystemTrayIconPrivate::updateMenu_sys()
     if (qpa_sys && menu) {
         addPlatformMenu(menu);
         qpa_sys->updateMenu(menu->platformMenu());
+
+    // Patch: Create a rich os x tray icon (pixel-perfect, theme switching).
+    } else if (qpa_sys) {
+        qpa_sys->updateMenu(nullptr);
     }
 #endif
 }
diff --git a/src/widgets/widgets/qabstractscrollarea.cpp b/src/widgets/widgets/qabstractscrollarea.cpp
index 598d173..fd2e636 100644
--- a/src/widgets/widgets/qabstractscrollarea.cpp
+++ b/src/widgets/widgets/qabstractscrollarea.cpp
@@ -655,15 +655,21 @@ scrolling range.
 QSize QAbstractScrollArea::maximumViewportSize() const
 {
     Q_D(const QAbstractScrollArea);
-    int hsbExt = d->hbar->sizeHint().height();
-    int vsbExt = d->vbar->sizeHint().width();
+    // Patch: Count the sizeHint of the bar only if it is displayed.
+    //int hsbExt = d->hbar->sizeHint().height();
+    //int vsbExt = d->vbar->sizeHint().width();
 
     int f = 2 * d->frameWidth;
     QSize max = size() - QSize(f + d->left + d->right, f + d->top + d->bottom);
-    if (d->vbarpolicy == Qt::ScrollBarAlwaysOn)
+    // Patch: Count the sizeHint of the bar only if it is displayed.
+    if (d->vbarpolicy == Qt::ScrollBarAlwaysOn) {
+        int vsbExt = d->vbar->sizeHint().width();
         max.rwidth() -= vsbExt;
-    if (d->hbarpolicy == Qt::ScrollBarAlwaysOn)
+    }
+    if (d->hbarpolicy == Qt::ScrollBarAlwaysOn) {
+        int hsbExt = d->hbar->sizeHint().height();
         max.rheight() -= hsbExt;
+    }
     return max;
 }