Describe the bug
The application does not terminate upon closing it. Trying to open it again results in a "This application is not open anymore" error. It needs to be force quit every time from the top left apple icon menu.

To Reproduce
Steps to reproduce the behavior:

1. Open the application
2. Try to quit - doesn't work
3. Close the application's window
4. The app still seems to be running in the dock, but clicking does nothing
5. Launch from spotlight produces the mentioned error.

Expected behavior
The application quits normally.

Video recording
http://files.wild.as/5Pirue

Environment (please complete the following information):

• OS: MacOS High sierra & Mojave, experienced the error on both.
• App Version 2.10.0

I tried to lookup the version number while in the "Closed but still running" state and the about window showed this up. I figured it might help.

A JavaScript error occurred in the main process
Uncaught Exception: Error: Object has been destroyed at mainWindow (/Applications/MJML.app/Contents/Resources/app.asar/webpack:/src/menu.js:26:13) at MenuItem.click (/Applications/MJML.app/Contents/Resources/electron.asar/browser/api/menu-item.js:52:9) at Function.executeCommand (/Applications/MJML.app/Contents/Resources/electron.asar/browser/api/menu.js:34:15)