QMenu: Ensure popup() gets the right screen geometry

Many QMenu related functions end up calling sizeHint() which
does call updateActionRects(). Since we try not to update the
action rects if no action has changed, we must be careful to
call it the first time with the right screen geometry. Other-
wise, multi-display setups may get the action rects based on
the wrong display.

In QMenu::popup(), this can be solved by using the position
passed as argument. Incidentally, we were already computing
the right display geometry in the same function, only a bit
later. The updated position around an eventual push button
menu should not change the screen onto which the menu popup
will be displayed.

Tested with the multiscreen-menus manual test.

Change-Id: Id7fc24be6908b4a9d24b8b9c8b8006efe45d69be
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

1 files changed, 11 insertions, 9 deletions

diff --git a/src/widgets/widgets/qmenu.cpp b/src/widgets/widgets/qmenu.cpp
index 75704f73de..2cafe462b1 100644
--- a/src/widgets/widgets/qmenu.cpp
+++ b/src/widgets/widgets/qmenu.cpp
@@ -2323,16 +2323,7 @@ void QMenu::popup(const QPoint &p, QAction *atAction)
     ensurePolished(); // Get the right font
     emit aboutToShow();
     const bool actionListChanged = d->itemsDirty;
-    d->updateActionRects();
-    QPoint pos;
-    QPushButton *causedButton = qobject_cast<QPushButton*>(d->causedPopup.widget);
-    if (actionListChanged && causedButton)
-        pos = QPushButtonPrivate::get(causedButton)->adjustedMenuPosition();
-    else
-        pos = p;
 
-    const QSize menuSizeHint(sizeHint());
-    QSize size = menuSizeHint;
     QRect screen;
 #ifndef QT_NO_GRAPHICSVIEW
     bool isEmbedded = !bypassGraphicsProxyWidget(this) && d->nearestGraphicsProxyWidget(this);
@@ -2341,6 +2332,17 @@ void QMenu::popup(const QPoint &p, QAction *atAction)
     else
 #endif
     screen = d->popupGeometry(QApplication::desktop()->screenNumber(p));
+    d->updateActionRects(screen);
+
+    QPoint pos;
+    QPushButton *causedButton = qobject_cast<QPushButton*>(d->causedPopup.widget);
+    if (actionListChanged && causedButton)
+        pos = QPushButtonPrivate::get(causedButton)->adjustedMenuPosition();
+    else
+        pos = p;
+
+    const QSize menuSizeHint(sizeHint());
+    QSize size = menuSizeHint;
     const int desktopFrame = style()->pixelMetric(QStyle::PM_MenuDesktopFrameWidth, 0, this);
     bool adjustToDesktop = !window()->testAttribute(Qt::WA_DontShowOnScreen);