From 75eeae6b42ccf9d553ccc77c3efcf69470540120 Mon Sep 17 00:00:00 2001
From: David Edmundson <kde@davidedmundson.co.uk>
Date: Tue, 25 Apr 2017 11:32:03 +0100
Subject: [PATCH] Update the ungrab mouse hack for Qt5.8

---
 applets/appmenu/lib/appmenuapplet.cpp | 27 +++++++++++++++++++++++---
 applets/systemtray/systemtray.cpp     | 28 ++++++++++++++++++++++++---
 2 files changed, 49 insertions(+), 6 deletions(-)

diff --git a/applets/appmenu/lib/appmenuapplet.cpp b/applets/appmenu/lib/appmenuapplet.cpp
index 9aaf5cc68..a88122dd0 100644
--- a/applets/appmenu/lib/appmenuapplet.cpp
+++ b/applets/appmenu/lib/appmenuapplet.cpp
@@ -30,6 +30,8 @@
 #include <QQuickWindow>
 #include <QScreen>
 #include <QDBusConnection>
+#include <QVersionNumber>
+#include <QTimer>
 
 AppMenuApplet::AppMenuApplet(QObject *parent, const QVariantList &data)
     : Plasma::Applet(parent, data)
@@ -159,10 +161,29 @@ void AppMenuApplet::trigger(QQuickItem *ctx, int idx)
     QMenu *actionMenu = createMenu(idx);
     if (actionMenu) {
 
-        if (ctx && ctx->window() && ctx->window()->mouseGrabberItem()) {
-            // FIXME event forge thing enters press and hold move mode :/
-            ctx->window()->mouseGrabberItem()->ungrabMouse();
+        //this is a workaround where Qt will fail to realise a mouse has been released
+        // this happens if a window which does not accept focus spawns a new window that takes focus and X grab
+        // whilst the mouse is depressed
+        // https://bugreports.qt.io/browse/QTBUG-59044
+        // this causes the next click to go missing
+
+        //by releasing manually we avoid that situation
+        auto ungrabMouseHack = [ctx]() {
+            if (ctx && ctx->window() && ctx->window()->mouseGrabberItem()) {
+                // FIXME event forge thing enters press and hold move mode :/
+                ctx->window()->mouseGrabberItem()->ungrabMouse();
+            }
+        };
+
+        //pre 5.8.0 QQuickWindow code is "item->grabMouse(); sendEvent(item, mouseEvent)"
+        //post 5.8.0 QQuickWindow code is sendEvent(item, mouseEvent); item->grabMouse()
+        if (QVersionNumber::fromString(qVersion()) > QVersionNumber(5, 8, 0)) {
+            QTimer::singleShot(0, this, ungrabMouseHack);
+        }
+        else {
+            ungrabMouseHack();
         }
+        //end workaround
 
         const auto &geo = ctx->window()->screen()->availableVirtualGeometry();
 
diff --git a/applets/systemtray/systemtray.cpp b/applets/systemtray/systemtray.cpp
index 098395d06..ec921e7c6 100644
--- a/applets/systemtray/systemtray.cpp
+++ b/applets/systemtray/systemtray.cpp
@@ -22,7 +22,8 @@
 
 #include <QDebug>
 #include <QProcess>
-
+#include <QVersionNumber>
+#include <QTimer>
 
 #include <QDBusConnection>
 #include <QDBusConnectionInterface>
@@ -163,9 +164,30 @@ void SystemTray::showPlasmoidMenu(QQuickItem *appletInterface, int x, int y)
     connect(this, &QObject::destroyed, desktopMenu, &QMenu::close);
     desktopMenu->setAttribute(Qt::WA_DeleteOnClose);
 
-    if (appletInterface->window() && appletInterface->window()->mouseGrabberItem()) {
-        appletInterface->window()->mouseGrabberItem()->ungrabMouse();
+    //this is a workaround where Qt will fail to realise a mouse has been released
+
+    // this happens if a window which does not accept focus spawns a new window that takes focus and X grab
+    // whilst the mouse is depressed
+    // https://bugreports.qt.io/browse/QTBUG-59044
+    // this causes the next click to go missing
+
+    //by releasing manually we avoid that situation
+    auto ungrabMouseHack = [appletInterface]() {
+        if (appletInterface->window() && appletInterface->window()->mouseGrabberItem()) {
+            appletInterface->window()->mouseGrabberItem()->ungrabMouse();
+        }
+    };
+
+    //pre 5.8.0 QQuickWindow code is "item->grabMouse(); sendEvent(item, mouseEvent)"
+    //post 5.8.0 QQuickWindow code is sendEvent(item, mouseEvent); item->grabMouse()
+    if (QVersionNumber::fromString(qVersion()) > QVersionNumber(5, 8, 0)) {
+        QTimer::singleShot(0, appletInterface, ungrabMouseHack);
+    }
+    else {
+        ungrabMouseHack();
     }
+    //end workaround
+
 
     emit applet->contextualActionsAboutToShow();
     foreach (QAction *action, applet->contextualActions()) {