4 files changed, 54 insertions, 4 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoainputcontext.mm b/src/plugins/platforms/cocoa/qcocoainputcontext.mm
index 9e3d747cd7..9221099a57 100644
--- a/src/plugins/platforms/cocoa/qcocoainputcontext.mm
+++ b/src/plugins/platforms/cocoa/qcocoainputcontext.mm
@@ -124,7 +124,22 @@ void QCocoaInputContext::connectSignals()
 void QCocoaInputContext::focusObjectChanged(QObject *focusObject)
 {
     Q_UNUSED(focusObject);
-    mWindow = QGuiApplication::focusWindow();
+    if (mWindow == QGuiApplication::focusWindow()) {
+        if (!mWindow)
+            return;
+
+        QCocoaWindow *window = static_cast<QCocoaWindow *>(mWindow->handle());
+        QNSView *view = qnsview_cast(window->view());
+        if (!view)
+            return;
+
+        if (NSTextInputContext *ctxt = [NSTextInputContext currentInputContext]) {
+            [ctxt discardMarkedText];
+            [view cancelComposingText];
+        }
+    } else {
+        mWindow = QGuiApplication::focusWindow();
+    }
 }
 
 void QCocoaInputContext::updateLocale()
diff --git a/src/plugins/platforms/cocoa/qnsview.h b/src/plugins/platforms/cocoa/qnsview.h
index a031853422..f8903725a6 100644
--- a/src/plugins/platforms/cocoa/qnsview.h
+++ b/src/plugins/platforms/cocoa/qnsview.h
@@ -63,6 +63,7 @@ Q_FORWARD_DECLARE_OBJC_CLASS(QT_MANGLE_NAMESPACE(QNSViewMouseMoveHelper));
     Qt::MouseButtons m_acceptedMouseDowns;
     Qt::MouseButtons m_frameStrutButtons;
     QString m_composingText;
+    QPointer<QObject> m_composingFocusObject;
     bool m_sendKeyEvent;
     QStringList *currentCustomDragTypes;
     bool m_dontOverrideCtrlLMB;
@@ -93,6 +94,7 @@ Q_FORWARD_DECLARE_OBJC_CLASS(QT_MANGLE_NAMESPACE(QNSViewMouseMoveHelper));
 - (void)textInputContextKeyboardSelectionDidChangeNotification : (NSNotification *) textInputContextKeyboardSelectionDidChangeNotification;
 - (void)viewDidHide;
 - (void)removeFromSuperview;
+- (void)cancelComposingText;
 
 - (BOOL)isFlipped;
 - (BOOL)acceptsFirstResponder;
diff --git a/src/plugins/platforms/cocoa/qnsview.mm b/src/plugins/platforms/cocoa/qnsview.mm
index 16207d8de8..011bbd9d08 100644
--- a/src/plugins/platforms/cocoa/qnsview.mm
+++ b/src/plugins/platforms/cocoa/qnsview.mm
@@ -1544,6 +1544,7 @@ static QTabletEvent::TabletDevice wacomTabletDevice(NSEvent *theEvent)
     }
 
     m_composingText.clear();
+    m_composingFocusObject = nullptr;
 }
 
 - (void) setMarkedText:(id)aString selectedRange:(NSRange)selectedRange replacementRange:(NSRange)replacementRange
@@ -1598,6 +1599,7 @@ static QTabletEvent::TabletDevice wacomTabletDevice(NSEvent *theEvent)
     m_composingText = preeditString;
 
     if (QObject *fo = m_platformWindow->window()->focusObject()) {
+        m_composingFocusObject = fo;
         QInputMethodQueryEvent queryEvent(Qt::ImEnabled);
         if (QCoreApplication::sendEvent(fo, &queryEvent)) {
             if (queryEvent.value(Qt::ImEnabled).toBool()) {
@@ -1610,6 +1612,25 @@ static QTabletEvent::TabletDevice wacomTabletDevice(NSEvent *theEvent)
     }
 }
 
+- (void)cancelComposingText
+{
+    if (m_composingText.isEmpty())
+        return;
+
+    if (m_composingFocusObject) {
+        QInputMethodQueryEvent queryEvent(Qt::ImEnabled);
+        if (QCoreApplication::sendEvent(m_composingFocusObject, &queryEvent)) {
+            if (queryEvent.value(Qt::ImEnabled).toBool()) {
+                QInputMethodEvent e;
+                QCoreApplication::sendEvent(m_composingFocusObject, &e);
+            }
+        }
+    }
+
+    m_composingText.clear();
+    m_composingFocusObject = nullptr;
+}
+
 - (void) unmarkText
 {
     if (!m_composingText.isEmpty()) {
@@ -1625,6 +1646,7 @@ static QTabletEvent::TabletDevice wacomTabletDevice(NSEvent *theEvent)
         }
     }
     m_composingText.clear();
+    m_composingFocusObject = nullptr;
 }
 
 - (BOOL) hasMarkedText
diff --git a/src/plugins/platforms/windows/qwindowscontext.cpp b/src/plugins/platforms/windows/qwindowscontext.cpp
index 6d4b7922db..7683f0da4d 100644
--- a/src/plugins/platforms/windows/qwindowscontext.cpp
+++ b/src/plugins/platforms/windows/qwindowscontext.cpp
@@ -65,6 +65,7 @@
 #include <qpa/qwindowsysteminterface.h>
 #include <qpa/qplatformnativeinterface.h>
 #include <QtGui/QGuiApplication>
+#include <QtGui/QOpenGLContext>
 
 #include <QtCore/QSet>
 #include <QtCore/QHash>
@@ -867,6 +868,18 @@ static inline bool resizeOnDpiChanged(const QWindow *w)
     return result;
 }
 
+static bool shouldHaveNonClientDpiScaling(const QWindow *window)
+{
+    return QSysInfo::windowsVersion() >= QSysInfo::WV_WINDOWS10
+        && window->isTopLevel()
+        && !window->property(QWindowsWindow::embeddedNativeParentHandleProperty).isValid()
+#if QT_CONFIG(opengl) // /QTBUG-62901, EnableNonClientDpiScaling has problems with GL
+        && (window->surfaceType() != QSurface::OpenGLSurface
+            || QOpenGLContext::openGLModuleType() != QOpenGLContext::LibGL)
+#endif
+       ;
+}
+
 /*!
      \brief Main windows procedure registered for windows.
 
@@ -988,10 +1001,8 @@ bool QWindowsContext::windowsProc(HWND hwnd, UINT message,
             d->m_creationContext->obtainedGeometry.moveTo(GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam));
             return true;
         case QtWindows::NonClientCreate:
-            if (QSysInfo::windowsVersion() >= QSysInfo::WV_WINDOWS10 && d->m_creationContext->window->isTopLevel()
-                && !d->m_creationContext->window->property(QWindowsWindow::embeddedNativeParentHandleProperty).isValid()) {
+            if (shouldHaveNonClientDpiScaling(d->m_creationContext->window))
                 enableNonClientDpiScaling(msg.hwnd);
-            }
             return false;
         case QtWindows::CalculateSize:
             return QWindowsGeometryHint::handleCalculateSize(d->m_creationContext->customMargins, msg, result);