Fix scrolldown arrow not showing on popup for QMenu

Scrolldown arrow was not shown when a taller than screen QMenu was
opened because the check to draw it used the size that was already
adjusted to the screen.

Fixed by using the actual menu size in the check. Also fixed the case
where the menu was scrolled, closed, and reopened, in which case the
size hint would return incorrect cached value. This led to scrolldown
arrow not being shown in case the menu was previously fully scrolled
down.

Task-number: QTBUG-27445
Change-Id: Icd8d774071662a9317b3ac53cb05b31cadba96ff
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
(cherry picked from qt5/qtbase commit fe8eb057fa05433e96de21df34871647f421f962))

1 files changed, 4 insertions, 2 deletions

diff --git a/src/gui/widgets/qmenu.cpp b/src/gui/widgets/qmenu.cpp
index 6e8c61c5db..77b6b21126 100644
--- a/src/gui/widgets/qmenu.cpp
+++ b/src/gui/widgets/qmenu.cpp
@@ -1823,6 +1823,8 @@ void QMenu::popup(const QPoint &p, QAction *atAction)
     Q_D(QMenu);
 #ifndef Q_OS_SYMBIAN
     if (d->scroll) { // reset scroll state from last popup
+        if (d->scroll->scrollOffset)
+            d->itemsDirty = 1; // sizeHint will be incorrect if there is previous scroll
         d->scroll->scrollOffset = 0;
         d->scroll->scrollFlags = QMenuPrivate::QMenuScroller::ScrollNone;
     }
@@ -1922,6 +1924,7 @@ void QMenu::popup(const QPoint &p, QAction *atAction)
     d->mousePopupPos = mouse;
     const bool snapToMouse = (QRect(p.x() - 3, p.y() - 3, 6, 6).contains(mouse));
 
+    const QSize menuSize(sizeHint());
     if (adjustToDesktop) {
         // handle popup falling "off screen"
         if (isRightToLeft()) {
@@ -1955,7 +1958,7 @@ void QMenu::popup(const QPoint &p, QAction *atAction)
 
         if (pos.y() < screen.top() + desktopFrame)
             pos.setY(screen.top() + desktopFrame);
-        if (pos.y() + size.height() - 1 > screen.bottom() - desktopFrame) {
+        if (pos.y() + menuSize.height() - 1 > screen.bottom() - desktopFrame) {
             if (d->scroll) {
                 d->scroll->scrollFlags |= uint(QMenuPrivate::QMenuScroller::ScrollDown);
                 int y = qMax(screen.y(),pos.y());
@@ -1967,7 +1970,6 @@ void QMenu::popup(const QPoint &p, QAction *atAction)
         }
     }
     const int subMenuOffset = style()->pixelMetric(QStyle::PM_SubMenuOverlap, 0, this);
-    const QSize menuSize(sizeHint());
     QMenu *caused = qobject_cast<QMenu*>(d_func()->causedPopup.widget);
     if (caused && caused->geometry().width() + menuSize.width() + subMenuOffset < screen.width()) {
         QRect parentActionRect(caused->d_func()->actionRect(caused->d_func()->currentAction));