3 files changed, 37 insertions, 0 deletions
diff --git a/src/plugins/platforms/windows/qwindowsnativeinterface.cpp b/src/plugins/platforms/windows/qwindowsnativeinterface.cpp
index ac7c22fb7e..babca35149 100644
--- a/src/plugins/platforms/windows/qwindowsnativeinterface.cpp
+++ b/src/plugins/platforms/windows/qwindowsnativeinterface.cpp
@@ -84,6 +84,9 @@ static int resourceType(const QByteArray &key)
     return int(result - names);
 }
 
+QWindowsWindowFunctions::WindowActivationBehavior QWindowsNativeInterface::m_windowActivationBehavior =
+    QWindowsWindowFunctions::DefaultActivateWindow;
+
 void *QWindowsNativeInterface::nativeResourceForWindow(const QByteArray &resource, QWindow *window)
 {
     if (!window || !window->handle()) {
@@ -253,6 +256,8 @@ QFunctionPointer QWindowsNativeInterface::platformFunction(const QByteArray &fun
         return QFunctionPointer(QWindowsWindow::setTouchWindowTouchTypeStatic);
     else if (function == QWindowsWindowFunctions::setHasBorderInFullScreenIdentifier())
         return QFunctionPointer(QWindowsWindow::setHasBorderInFullScreenStatic);
+    else if (function == QWindowsWindowFunctions::setWindowActivationBehaviorIdentifier())
+        return QFunctionPointer(QWindowsNativeInterface::setWindowActivationBehavior);
     return Q_NULLPTR;
 }
 
diff --git a/src/plugins/platforms/windows/qwindowsnativeinterface.h b/src/plugins/platforms/windows/qwindowsnativeinterface.h
index 3a0d3398d9..9fc43ddcce 100644
--- a/src/plugins/platforms/windows/qwindowsnativeinterface.h
+++ b/src/plugins/platforms/windows/qwindowsnativeinterface.h
@@ -42,6 +42,7 @@
 
 #include <QtGui/qfont.h>
 #include <QtGui/qpa/qplatformnativeinterface.h>
+#include <QtPlatformHeaders/qwindowswindowfunctions.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -96,7 +97,15 @@ public:
     QVariant windowProperty(QPlatformWindow *window, const QString &name, const QVariant &defaultValue) const Q_DECL_OVERRIDE;
     void setWindowProperty(QPlatformWindow *window, const QString &name, const QVariant &value) Q_DECL_OVERRIDE;
 
+    static QWindowsWindowFunctions::WindowActivationBehavior windowActivationBehavior()
+        { return QWindowsNativeInterface::m_windowActivationBehavior; }
+    static void setWindowActivationBehavior(QWindowsWindowFunctions::WindowActivationBehavior b)
+        { QWindowsNativeInterface::m_windowActivationBehavior = b; }
+
     QFunctionPointer platformFunction(const QByteArray &function) const Q_DECL_OVERRIDE;
+
+private:
+    static QWindowsWindowFunctions::WindowActivationBehavior m_windowActivationBehavior;
 };
 
 QT_END_NAMESPACE
diff --git a/src/plugins/platforms/windows/qwindowswindow.cpp b/src/plugins/platforms/windows/qwindowswindow.cpp
index 4c503a2c48..c1a047e276 100644
--- a/src/plugins/platforms/windows/qwindowswindow.cpp
+++ b/src/plugins/platforms/windows/qwindowswindow.cpp
@@ -43,6 +43,7 @@
 #include "qwindowsdrag.h"
 #include "qwindowsscreen.h"
 #include "qwindowsintegration.h"
+#include "qwindowsnativeinterface.h"
 #include "qwindowsopenglcontext.h"
 #ifdef QT_NO_CURSOR
 #  include "qwindowscursor.h"
@@ -2083,8 +2084,30 @@ void QWindowsWindow::requestActivateWindow()
     // 'Active' state handling is based in focus since it needs to work for
     // child windows as well.
     if (m_data.hwnd) {
+#ifndef Q_OS_WINCE
+        const DWORD currentThread = GetCurrentThreadId();
+        bool attached = false;
+        DWORD foregroundThread = 0;
+
+        // QTBUG-14062, QTBUG-37435: Windows normally only flashes the taskbar entry
+        // when activating windows of inactive applications. Attach to the input of the
+        // currently active window while setting the foreground window to always activate
+        // the window when desired.
+        if (QGuiApplication::applicationState() != Qt::ApplicationActive
+            && QWindowsNativeInterface::windowActivationBehavior() == QWindowsWindowFunctions::AlwaysActivateWindow) {
+            if (const HWND foregroundWindow = GetForegroundWindow()) {
+                foregroundThread = GetWindowThreadProcessId(foregroundWindow, NULL);
+                if (foregroundThread && foregroundThread != currentThread)
+                    attached = AttachThreadInput(foregroundThread, currentThread, TRUE) == TRUE;
+            }
+        }
+#endif // !Q_OS_WINCE
         SetForegroundWindow(m_data.hwnd);
         SetFocus(m_data.hwnd);
+#ifndef Q_OS_WINCE
+        if (attached)
+            AttachThreadInput(foregroundThread, currentThread, FALSE);
+#endif // !Q_OS_WINCE
     }
 }