restore window maximized state on toggle

Otherwise the window will have a maximized size but not maximized state after toggling it from system tray

autotests/windowcontrollertest.cpp

@@ -73,6 +73,16 @@ void WindowControllerTest::toggle()
     instance.toggleWindow();
     QCOMPARE(window.windowState(), Qt::WindowNoState);
     QCOMPARE(window.isVisible(), false);
+
+    // make sure we restore maximized state when toggling
+    instance.toggleWindow();
+    window.setVisibility(QWindow::Maximized);
+    QCOMPARE(window.windowState(), Qt::WindowMaximized);
+    instance.toggleWindow();
+    QCOMPARE(window.isVisible(), false);
+    instance.toggleWindow();
+    QCOMPARE(window.windowState(), Qt::WindowMaximized);
+    QCOMPARE(window.isVisible(), true);
 }
 
 QTEST_MAIN(WindowControllerTest)

src/app/windowcontroller.cpp

@@ -32,6 +32,16 @@ void WindowController::setWindow(QWindow *window)
 {
     m_window = window;
 
+    if (window != nullptr) {
+        // to restore maximized state after reopening from the system tray
+        connect(m_window, &QWindow::windowStateChanged, this, [this]() {
+            if (m_window->isVisible()) {
+                m_wasMaximized = m_window->windowStates() & Qt::WindowMaximized;
+            }
+        });
+        m_wasMaximized = m_window->windowStates() & Qt::WindowMaximized;
+    }
+
     Q_EMIT windowChanged();
 }
 
@@ -46,8 +56,12 @@ void WindowController::showAndRaiseWindow(const QString &startupId)
         return;
     }
     if (!m_window->isVisible()) {
+        if (m_wasMaximized) {
+            m_window->showMaximized();
+        } else {
             m_window->show();
         }
+    }
 
 #ifdef HAVE_WINDOWSYSTEM
     if (!startupId.isEmpty()) {

src/app/windowcontroller.h

@@ -67,5 +67,6 @@ Q_SIGNALS:
 private:
     WindowController() = default;
 
+    bool m_wasMaximized;
     QWindow *m_window = nullptr;
 };