Fix QWindowPrivate::globalPosition() for foreign windows

Use mapToGlobal(QPoint(0, 0)) when encountering a foreign window in
the parent hierarchy as it is not clear whether it is a native
top level or child. In the latter case, using the position is not
sufficient.

Task-number: QTBUG-43252
Change-Id: I5eebb1f0dbc6a0abbd968c5d383d3eded75c11a5
Reviewed-by: Jan Arve Sæther <jan-arve.saether@theqtcompany.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/src/gui/kernel/qwindow_p.h b/src/gui/kernel/qwindow_p.h
index ccd14f66ae..4020376feb 100644
--- a/src/gui/kernel/qwindow_p.h
+++ b/src/gui/kernel/qwindow_p.h
@@ -125,8 +125,14 @@ public:
     QPoint globalPosition() const {
         Q_Q(const QWindow);
         QPoint offset = q->position();
-        for (const QWindow *p = q->parent(); p; p = p->parent())
-            offset += p->position();
+        for (const QWindow *p = q->parent(); p; p = p->parent()) {
+            if (p->type() != Qt::ForeignWindow) {
+                offset += p->position();
+            } else { // QTBUG-43252, mapToGlobal() for foreign children.
+                offset += p->mapToGlobal(QPoint(0, 0));
+                break;
+            }
+        }
         return offset;
     }