It’s almost eighteen months since I first posted about the noticeable “Rise and Rise of the Mail-like Look” in many apps. Yojimbo, SOHO Smart Notes, ecto and many more have since followed suit, so that Fraser Spiers’ “Exposé confusion” is a greater danger than ever.

If you fancy an even more unified GUI across all your apps, UNO is the utility for you.

An updated version has just been released which brings the Mail-like look of a unified Toolbar/Titlebar and lighter metal look to all the windows in your system. Its aim is “to enhance aqua interface consistency, by making all elements look and feel as one.”

UNO 1.5 has been completely rewritten. Some annoying glitches (the QuickTime window, for example) are now fixed, and the developers have produced a wider range of skins for iTunes.

The app’s main interface offers a preview of how your system will look after applying the tweak:

Notice also the Uninstall button which allows you to unwind the changes easily if you want to return to vanilla Mac OS X.

In this version, Mail.app gets some special treatment. After applying UNO, the lozenge-shaped buttons are replaced with Safari- or Finder-like rectangular buttons and the unread mail icon is “aquafied”:

This is only an option though. If you like UNO’s consistent style and the default lozenged-up look of Tiger Mail you can choose that combination in the interface option drop-down boxes on the left of the main screen.

You can read more about UNO and view the entire 1.5 changelog on the developer’s web site.

UNO is free-ware (donations not refused) and is available from the app’s website .