Fail with timer-auto-close prompt if the file already exists.

[xenon-2000]

When a file already exists and I choose to save from my custom folder list tree, it silently saves the file and appends (1) to the file name. I would like it to fail if the file name already exists and show a prompt to either "Save As" so I can manually pick path/name. Or a cancel button that the window will auto close in #### ms.