Like many folks I was delighted to hear that not only was Twitter for Mac 2.0 (née Tweetie) still alive, and not only was Twitter Inc. finally behind the project (and not just in the sense of letting Loren Brichter work on it in his spare hours), but it was done and due for release as a Mac App Store launch title. It's already my regular desktop Twitter client, replacing Echofon for Mac, which replaced the old Tweetie 1.0.

The new Twitter/Mac is a better-than-decent app, but flawed. Like the first Tweetie it has an innovative visual design that aims to bring some iOS flavor to the Mac desktop. In this new version, that means using lots of Helvetica instead of Lucida Grande. It also means the tweet input boxes are more like iPad popovers than Mac OS windows, with no title bar and a modal 'cancel' button instead of the familiar upper-left-hand "traffic light."

I wish I could say it's everything I hoped it would be. The old Tweetie was a great app, and if it had had native retweet support (which the new one does) I'd have kept on using it. This new one does have all the new features I want, like real-time user streams. But unlike Echofon (and Twitter/iPad, and the #newtwitter web UI) it tries to cram an awful lot of information into a single pane. That's not a crazy decision (and it is consistent with the original Tweetie/Twitter for iPhone), but it feels like a poor use of space even on my laptop screen.

Echofon isn't nearly as pretty, but it does give you an optional, easily hideable side drawer for viewing user info or conversations without losing sight of your main tweet stream. While a drawer would be a terrible fit for Twitter/Mac's unique (and gorgeous) UI style, I could easily see them doing something like Sparrow's right-hand message pane, which can be shown or hidden with a click or keystroke.

All that being said, these are just design choices I disagree with. There are also a few obvious errors:

• The main (and only) window has a set of "traffic light" buttons in the upper left hand corner. Except they're not the familiar red, yellow and green—they're black buttons on a black tab bar. Black on black is sexy, but it's terrible for usability. (Would it have killed them to have the buttons turn colored on mouseover? Or to just make them colored all the time?)

  Worse, the rightmost maximize (green) button isn't even functional. It does nothing.

• Also, if you're a Spaces user (like I am) you may or may not have noticed that since the 2.0.1 software update came out the other day, the Twitter window always appears in every Space whether you want it to or not. After a brief Twitter convo with some friends it looked like the solution was to go into System Preferences and pin Twitter to a particular Space, like Space 1. This seemed to work until the next time I relaunched the app, but now has stopped working, and every time I switch Spaces there's Twitter, right in the middle of a desktop where it's not wanted.

Of course, even Apple's own apps can demonstrate some wonky behavior when switching Spaces. It's a feature Apple seems not too interested in improving to a point where even their own developers can reliably get their apps to work with it turned on. But it's also an extremely handy feature I use dozens of times a day, and the vast majority of traditional Cocoa apps work fine with it. ("Working fine" here means that their windows stay where I fucking put them, even across multiple Spaces.)

The only other app I use day-to-day that has this much difficulty playing nicely with Spaces is TextMate. TextMate is practically abandonware, and I'd bet most of its window drawing code dates back to the Mac OS X 10.4 days, so it's not that surprising it has problems.

Twitter has no excuse. Twitter for Mac is a new app, based on a previously released app that (if memory serves) had a functional set of traffic-light buttons and never had a problem with Spaces support.

At this point, I have to wonder if this Spaces weirdness is a mistake or intentional. Either way it's annoying and I want it to stop.