Nested file not saving changes when unnested

[FutureTD]

Installed product versions

• Visual Studio: 2017
• This extension: 2.6.84

Current behavior

If you nest a class and make changes to the nested class and save and then you un-nest the class, it does not keep the original changes made to the file while it was nested.

It reverts the class back to before it was nested.

Expected behavior

Changes made to a file while nested should be there when un-nested.