closeEvent() should always hide the window, never raise it.

This fixes an issue on X11 where Alt-F4 would not close the window, due
to toggleWindow() believing the window is inactive and trying to raise
it.  Avoid the problem by closing the window unconditionally.

src/gui/MainWindow.cpp

@@ -612,7 +612,7 @@ void MainWindow::closeEvent(QCloseEvent* event)
     if (minimizeOnClose && !appExitCalled)
     {
         event->ignore();
-        toggleWindow();
+        hideWindow();
 
         if (config()->get("security/lockdatabaseminimize").toBool()) {
             m_ui->tabWidget->lockDatabases();
@@ -777,15 +777,20 @@ void MainWindow::trayIconTriggered(QSystemTrayIcon::ActivationReason reason)
     }
 }
 
-void MainWindow::toggleWindow()
+void MainWindow::hideWindow()
 {
-    if ((QApplication::activeWindow() == this) && isVisible() && !isMinimized()) {
     setWindowState(windowState() | Qt::WindowMinimized);
     QTimer::singleShot(0, this, SLOT(hide()));
 
     if (config()->get("security/lockdatabaseminimize").toBool()) {
         m_ui->tabWidget->lockDatabases();
     }
+}
+
+void MainWindow::toggleWindow()
+{
+    if ((QApplication::activeWindow() == this) && isVisible() && !isMinimized()) {
+        hideWindow();
     } else {
         ensurePolished();
         setWindowState(windowState() & ~Qt::WindowMinimized);

src/gui/MainWindow.h

@@ -72,6 +72,7 @@ private Q_SLOTS:
     void rememberOpenDatabases(const QString& filePath);
     void applySettingsChanges();
     void trayIconTriggered(QSystemTrayIcon::ActivationReason reason);
+    void hideWindow();
     void toggleWindow();
     void lockDatabasesAfterInactivity();
     void repairDatabase();