And I believe perl/tk doesn't work at all on older versions of MacOS X, so choosing perl/tk means locking out users who haven't stayed on the $130/version upgrade treadmill. My perl/tk app was meant to be cross-platform, but I ended up deciding not to support it any more on any platform but Linux, because supporting Windows users was eating up large amounts of my time, and it was an open-source project that I wasn't making any money on. No matter how cross-platform one of these toolkits is supposed to be, I think making an app cross-platform still requires an order of magnitude more maintenance work once the app is mature. I've also soured on the whole idea of bringing OSS to the Windows-using masses -- I think it just sucks energy out of the OSS movement, and there's no real return on the investment, because those folks are happy with Windows, and are going to keep on using it.