Fix a bug where the window would sometimes not show up after restoring from tray

After this patch, the window will not have the window manager's restore animation anymore, but will be reliably shown

src/gui/MainWindow.cpp

@@ -728,18 +728,19 @@ void MainWindow::toggleWindow()
 {
     if ((QApplication::activeWindow() == this) && isVisible() && !isMinimized()) {
         setWindowState(windowState() | Qt::WindowMinimized);
-        hide();
-
+        QTimer::singleShot(0, this, SLOT(hide()));
+        
         if (config()->get("security/lockdatabaseminimize").toBool()) {
             m_ui->tabWidget->lockDatabases();
         }
-    }
-    else {
+    } else {
         ensurePolished();
-        show();
         setWindowState(windowState() & ~Qt::WindowMinimized);
-        raise();
-        activateWindow();
+        QTimer::singleShot(0, this, [this]() {
+            show();
+            raise();
+            activateWindow();
+        });
         
 #if defined(Q_OS_LINUX) && ! defined(QT_NO_DBUS)
         // re-register global D-Bus menu (needed on Ubuntu with Unity)