Closing a tab before content loaded, causes a crash

1. Load a few files.
2. Close the IDE.
3. When re-opening, files are lazyloaded.      
4. To to the last tab and start pressing control+w.

I think the crash is because we close an editor, before the content is loaded.

Migrated from https://gitlab.com/codepointer/codepointer/-/issues/7