I'm sorry this was your experience working in our third generation editor. I am glad continuing to reuse your templates is a workaround that works for you in the meantime. Please let us know if you have any questions or concerns as you continue to work in your email. We're here if you need any help with any of your templates!
Our Advanced Editor for custom code emails is still available! You can access this editor by clicking Create under the Campaigns tab of your account. You'll then get a pop-up where you have to select Email and click "Custom code" in the top right hand corner.
You're very welcome! I'm glad we could help point you in the right direction. Please reach out again if you have any further questions or concerns.