QNX: Fix retrieving the window group name

The code assumes that there is a root window, and crashed
otherwise.

Task-number: QTBUG-35121
Change-Id: Idbf0e0bfc03cd427f0aab81db88b34fe94228c81
Reviewed-by: Rafael Roquetto <rafael.roquetto@kdab.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/plugins/platforms/qnx/qqnxnativeinterface.cpp b/src/plugins/platforms/qnx/qqnxnativeinterface.cpp
index 8958a5c1e2..24af5c2683 100644
--- a/src/plugins/platforms/qnx/qqnxnativeinterface.cpp
+++ b/src/plugins/platforms/qnx/qqnxnativeinterface.cpp
@@ -52,11 +52,13 @@ QT_BEGIN_NAMESPACE
 void *QQnxNativeInterface::nativeResourceForWindow(const QByteArray &resource, QWindow *window)
 {
     if (resource == "windowGroup" && window && window->screen()) {
-        const QQnxScreen * const screen = static_cast<QQnxScreen *>(window->screen()->handle());
+        QQnxScreen * const screen = static_cast<QQnxScreen *>(window->screen()->handle());
         if (screen) {
+            screen_window_t screenWindow = reinterpret_cast<screen_window_t>(window->winId());
+            QQnxWindow *qnxWindow = screen->findWindow(screenWindow);
             // We can't just call data() instead of constData() here, since that would detach
             // and the lifetime of the char * would not be long enough. Therefore the const_cast.
-            return const_cast<char *>(screen->rootWindow()->groupName().constData());
+            return qnxWindow ? const_cast<char *>(qnxWindow->groupName().constData()) : 0;
         }
     }