The crash occurs during a "self.editFont.config" call, when the sample text in the font dialog is updated with new font properties. My changes re-structures the configure event to first create a tuple with new font properties, then apply that to the parent label widget's font. Same effect, works around the crash. 

My testing shows the crash occurs at the event loop level--somewhere in the event loop between Python, Tk, and Cocoa, this specific configuration causes Tk to barf and then crash. If you have followed the traffic on the event loop issues in Tk-Cocoa at SF and the Tcl-Mac list, you're aware that a) the event loop is fragile and complex and b) pretty much impossible to solve at this time because the only one who really understands it well, the original author of the code, is no longer involved with Tk development. As a result, it is often simpler to work around Tk-Cocoa event loop issues at the script level: that is what my patch does.  There is little chance of solving the crash at the Tk level at this time. 

I don't understand what the problem with in requesting that IDLE users update their installation to get this patch; it's no different than any other bug fix. As far as making sure it works with the various releases of Python, that's work that you or another Python dev will have to do. It's a two-line fix so I doubt it will be that complicated to implement. And yes, in an ideal world, it would be better to fix Tk, but this patch solve the immediate problem because we are not able to address this issue at the Tk level at this time.