diff --git a/src/private/FloatingWindow.cpp b/src/private/FloatingWindow.cpp
index 8c7987c7..9cc01cab 100644
--- a/src/private/FloatingWindow.cpp
+++ b/src/private/FloatingWindow.cpp
@@ -488,6 +488,8 @@ bool FloatingWindow::event(QEvent *ev)
     } else if (ev->type() == QEvent::StatusTip && parent()) {
         // show status tips in the main window
         return parent()->event(ev);
+    } else if (ev->type() == QEvent::LayoutRequest) {
+        updateSizeConstraints();
     }
 
     return QWidgetAdapter::event(ev);
@@ -562,6 +564,10 @@ void FloatingWindow::updateSizeConstraints()
 {
     // Doing a delayed call to make sure the layout has completled any ongoing operation.
     QMetaObject::invokeMethod(this, [this] {
+        // Not simply using layout's max-size support because
+        // 1) that's not portable to QtQuick
+        // 2) QStackedLayout (from tab-widget) doesn't propagate size constraints up
+        // Doing it manually instead.
         setMaximumSize(maxSizeHint());
     }, Qt::QueuedConnection);
 }
diff --git a/tests/tst_docks.cpp b/tests/tst_docks.cpp
index cf112565..5ad2f8fb 100644
--- a/tests/tst_docks.cpp
+++ b/tests/tst_docks.cpp
@@ -228,6 +228,7 @@ private Q_SLOTS:
     void tst_titlebar_getter();
     void tst_raise();
     void tst_addingOptionHiddenTabbed();
+    void tst_maxSizedFloatingWindow();
     void tst_maxSizedHonouredAfterRemoved();
     void tst_addDockWidgetAsTabToDockWidget();
     void tst_close();
@@ -6407,6 +6408,42 @@ void TestDocks::tst_flagDoubleClick()
     }
 }
 
+void TestDocks::tst_maxSizedFloatingWindow()
+{
+    // Tests that FloatingWindows get a proper max-size, if its dock widget has one
+    EnsureTopLevelsDeleted e;
+    auto dock1 = new DockWidgetType("dock1");
+    auto dock2 = new DockWidgetType("dock2");
+    auto w = new MyWidget("foo");
+    w->setMinimumSize(120, 100);
+    w->setMaximumSize(300, 300);
+    dock1->setWidget(w);
+
+    dock1->show();
+    dock2->show();
+
+    auto window1 = dock1->window();
+    auto window2 = dock2->window();
+    Testing::waitForEvent(window1, QEvent::LayoutRequest);
+
+    QVERIFY(window1->maximumSize().width() < 500);
+    QVERIFY(window1->maximumSize().height() < 500);
+    QVERIFY(window2->maximumSize().width() > 500);
+    QVERIFY(window2->maximumSize().height() > 500);
+
+    // Adding side-by-side, we don't honour max size (yet)
+    dock1->addDockWidgetToContainingWindow(dock2, Location_OnBottom);
+    Testing::waitForEvent(window1, QEvent::LayoutRequest);
+    QVERIFY(window1->maximumSize().width() > 500);
+    QVERIFY(window1->maximumSize().height() > 500);
+
+    // Close dw2, we have a single dock widget again, we honour max-size
+    dock2->close();
+    Testing::waitForEvent(window1, QEvent::LayoutRequest);
+    QVERIFY(window1->maximumSize().width() < 500);
+    QVERIFY(window1->maximumSize().height() < 500);
+}
+
 void TestDocks::tst_maxSizedHonouredAfterRemoved()
 {
     EnsureTopLevelsDeleted e;