Apple Mail attachment issue - can't it just stay as an icon?

Can't my attachment just stay as an icon? I was trying to attach a PDF document to my email. It will auto display itself as an inline content in my email. Yes, I can choose to display it as an icon but it will always auto display itself as an inline content again when i re-open the email.

When is Apple going to fix this issue? I don't feel like buying a 3rd party email client to replace this app that already comes with my macbook.