Fix focus handling when the application has QAxWidgets.

Removed old defunct platform specific code from
QWidget::isActiveWindow() and added call to
QPlatformWindow::isActive() instead. This is done because
the embedded native windows inside QAxWidgets can have
focus but are not part of the parent application's Qt
window hierarchy, so native methods are required to determine
if they are part of the active window or not.

QWidgetPrivate::setFocus_sys() was implemented to activate
the window of the focused widget if the focus was elsewhere.
This is required because embedded native windows can steal the
focus from the main application window.

Focus event handling in Windows platform adaptation plugin was
fixed to correctly identify the active window in cases where
the are embedded native widgets that can have focus.

Also fixed three test cases that were affected by these changes.

Task-number: QTBUG-25852
Task-number: QTBUG-23699
Change-Id: I817e0ce4317e88955bb49b034eacd630a876ccf0
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>

2 files changed, 19 insertions, 2 deletions

diff --git a/src/plugins/platforms/windows/qwindowscontext.cpp b/src/plugins/platforms/windows/qwindowscontext.cpp
index 92c92676bb..2c9750a327 100644
--- a/src/plugins/platforms/windows/qwindowscontext.cpp
+++ b/src/plugins/platforms/windows/qwindowscontext.cpp
@@ -551,6 +551,22 @@ QWindowsWindow *QWindowsContext::findPlatformWindow(HWND hwnd) const
     return d->m_windows.value(hwnd);
 }
 
+QWindowsWindow *QWindowsContext::findClosestPlatformWindow(HWND hwnd) const
+{
+    QWindowsWindow *window = d->m_windows.value(hwnd);
+
+    // Requested hwnd may also be a child of a platform window in case of embedded native windows.
+    // Find the closest parent that has a platform window.
+    if (!window) {
+        for (HWND w = hwnd; w; w = GetParent(w)) {
+            if (window = d->m_windows.value(w))
+                return window;
+        }
+    }
+
+    return window;
+}
+
 QWindow *QWindowsContext::findWindow(HWND hwnd) const
 {
     if (const QWindowsWindow *bw = findPlatformWindow(hwnd))
@@ -871,8 +887,8 @@ void QWindowsContext::handleFocusEvent(QtWindows::WindowsEventType et,
     } else {
         // Focus out: Is the next window known and different
         // from the receiving the focus out.
-        if (const HWND nextActiveHwnd = GetActiveWindow())
-            if (QWindowsWindow *nextActivePlatformWindow = findPlatformWindow(nextActiveHwnd))
+        if (const HWND nextActiveHwnd = GetFocus())
+            if (QWindowsWindow *nextActivePlatformWindow = findClosestPlatformWindow(nextActiveHwnd))
                 if (nextActivePlatformWindow != platformWindow)
                     nextActiveWindow = nextActivePlatformWindow->window();
     }
diff --git a/src/plugins/platforms/windows/qwindowscontext.h b/src/plugins/platforms/windows/qwindowscontext.h
index 4b221bdba3..e95ea7f3f4 100644
--- a/src/plugins/platforms/windows/qwindowscontext.h
+++ b/src/plugins/platforms/windows/qwindowscontext.h
@@ -152,6 +152,7 @@ public:
     void addWindow(HWND, QWindowsWindow *w);
     void removeWindow(HWND);
 
+    QWindowsWindow *findClosestPlatformWindow(HWND) const;
     QWindowsWindow *findPlatformWindow(HWND) const;
     QWindow *findWindow(HWND) const;
     QWindowsWindow *findPlatformWindowAt(HWND parent, const QPoint &screenPoint,