Fix macOS window activation issues

Reverts part of 34b7d08a5, which introduced a regression.

src/gui/Application.cpp

@@ -212,6 +212,12 @@ bool Application::event(QEvent* event)
         emit openFile(static_cast<QFileOpenEvent*>(event)->file());
         return true;
     }
+#ifdef Q_OS_MACOS
+    // restore main window when clicking on the docker icon
+    else if (event->type() == QEvent::ApplicationActivate) {
+        emit applicationActivated();
+    }
+#endif
 
     return QApplication::event(event);
 }