From 3d71c4b740d23d5c3f380f495990f35ea17dc2a0 Mon Sep 17 00:00:00 2001
From: Volker Hilsheimer <volker.hilsheimer@qt.io>
Date: Wed, 5 May 2021 12:30:45 +0200
Subject: [PATCH] QWindow: synthesize a QContextMenuEvent from relevant mouse
 events
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QWindow receives keyboard originated context menu events, so it should
also receive events originating from a right-button mouse event.

Remove the incorrect statement about the special acceptance flag for
context menu events. There is no such thing, the event gets delievered
after the corresponding mouse press/release event.

Fixes: QTBUG-59988
Task-number: QTBUG-93486
Change-Id: I148310440604e74f600932cc1898fa152c483a61
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
---
 src/gui/kernel/qevent.cpp  |  5 -----
 src/gui/kernel/qwindow.cpp | 30 ++++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/src/gui/kernel/qevent.cpp b/src/gui/kernel/qevent.cpp
index 7e5e7ac703..858a7cba2e 100644
--- a/src/gui/kernel/qevent.cpp
+++ b/src/gui/kernel/qevent.cpp
@@ -1934,11 +1934,6 @@ QIconDragEvent::~QIconDragEvent()
 
     When this event occurs it is customary to show a QMenu with a
     context menu, if this is relevant to the context.
-
-    Context menu events contain a special accept flag that indicates
-    whether the receiver accepted the event. If the event handler does
-    not accept the event then, if possible, whatever triggered the event will be
-    handled as a regular input event.
 */
 
 #ifndef QT_NO_CONTEXTMENU
diff --git a/src/gui/kernel/qwindow.cpp b/src/gui/kernel/qwindow.cpp
index 7b0f977458..bacc49a98e 100644
--- a/src/gui/kernel/qwindow.cpp
+++ b/src/gui/kernel/qwindow.cpp
@@ -41,6 +41,9 @@
 
 #include <qpa/qplatformwindow.h>
 #include <qpa/qplatformintegration.h>
+#ifndef QT_NO_CONTEXTMENU
+#include <qpa/qplatformtheme.h>
+#endif
 #include "qsurfaceformat.h"
 #ifndef QT_NO_OPENGL
 #include <qpa/qplatformopenglcontext.h>
@@ -2491,6 +2494,33 @@ bool QWindow::event(QEvent *ev)
     default:
         return QObject::event(ev);
     }
+
+#ifndef QT_NO_CONTEXTMENU
+    /*
+        QGuiApplicationPrivate::processContextMenuEvent blocks mouse-triggered
+        context menu events that the QPA plugin might generate. In practice that
+        never happens, as even on Windows WM_CONTEXTMENU is never generated by
+        the OS (we never call the default window procedure that would do that in
+        response to unhandled WM_RBUTTONUP).
+
+        So, we always have to syntheize QContextMenuEvent for mouse events anyway.
+        QWidgetWindow synthesizes QContextMenuEvent similar to this code, and
+        never calls QWindow::event, so we have to do it here as well.
+
+        This logic could be simplified by always synthesizing events in
+        QGuiApplicationPrivate, or perhaps even in each QPA plugin. See QTBUG-93486.
+    */
+    static const QEvent::Type contextMenuTrigger =
+        QGuiApplicationPrivate::platformTheme()->themeHint(QPlatformTheme::ContextMenuOnMouseRelease).toBool() ?
+        QEvent::MouseButtonRelease : QEvent::MouseButtonPress;
+    if (QMouseEvent *me = static_cast<QMouseEvent *>(ev);
+        ev->type() == contextMenuTrigger && me->button() == Qt::RightButton) {
+        QSinglePointEvent *pev = static_cast<QSinglePointEvent*>(ev);
+        QContextMenuEvent e(QContextMenuEvent::Mouse, me->position().toPoint(),
+                            pev->globalPosition().toPoint(), pev->modifiers());
+        QGuiApplication::sendEvent(this, &e);
+    }
+#endif
     return true;
 }