Hide the "Don't Save" button when discarding a file isn't a desired behavior

[phated]

Currently, if a file is a brand new (unsaved) file, the Save/Save As prompt has a "Don't Save" button. This is desired when a user attempts to change from a new file to a previously saved file and is prompted to save. However, this is incorrect UI behavior when the user is just using the Save/Save As functionality of the editor. We need to hide the "Don't Save" button when we are not in the "Changing File" mode.

[PropGit]

NOTE: This is a new behavior (bug) in v0.7.1; it did not behave this way in v0.7.0 as you can see about 20 seconds into this video that was recorded for issues #235.

It seems to only happen incorrectly when it is a new file and either the Save or Save As operation is user-activated. After it is saved, an Save As operation shows the right dialog (with no "Don't Save" button).

[PropGit]

Verified fixed. However, this has led to a side effect noted in issue #268.