Progress-bar for tracking the upload of attachments

[sparklywater]

Currently, when uploading attachments only a small notification is displayed saying 'Uploading - please wait'. When uploading larger files, users get confused about the progress of their upload because there is no real progress-bar to show the stage their upload has reached at a specific time.

My request is a mod which places a real-time progress bar in the attachments popup window which allows users to track the progress of their uploads.