diff --git a/applets/systemtray/systemtray.cpp b/applets/systemtray/systemtray.cpp
--- a/applets/systemtray/systemtray.cpp
+++ b/applets/systemtray/systemtray.cpp
@@ -32,6 +32,8 @@
 #include <QQuickWindow>
 #include <QRegExp>
 #include <QScreen>
+#include <QTimer>
+#include <QVersionNumber>
 #include <QStandardItemModel>
 
 #include <Plasma/PluginLoader>
@@ -163,9 +165,29 @@
     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 = [=]() {
+        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, this, ungrabMouseHack);
+    }
+    else {
+        ungrabMouseHack();
     }
+    // end workaround
 
     emit applet->contextualActionsAboutToShow();
     foreach (QAction *action, applet->contextualActions()) {