Saving vs. Submitting case
It is important to understand difference between saving the case editor and submitting changes to the server. Saving the editor (using Save command by keyboard shortcut or Save icon) saves changes locally, but it does not send your changes to the FogBugz server. Saving changes locally is useful for example when you are working offline, with no connection to the FogBugz server, or when preparing longer comment.
To send changes to FogBugz server, you need to use Submit button.
Attachments are always sent immediately, it is not possible to save attachment locally for later submission.