This happens to me often enough. While typing in my editor, I'll get a the Mac version of the hourglass (rainbow spinning disc) for awhile while I'm the middle of typing an expression. Then I'll get a crash message from eclipse. Failed to update model based on selection: java.lang.StackOverflowError It seems like this only happens when I'm in the middle of typing an expression that is incomplete. Almost as if the editor is trying to a syntax check while I'm typing and failing on it. In fact, while typing this bug report, I dismissed that crash message and it immediately happened again. This time, though, since I didn't leave the crash window open (no need to remember the content), when I clicked OK, it didn't repeat. I don't have the "Report problems as you type" box checked in the ruby editor settings, nor do I have editor spell checking enabled. Of course, I can see why you would still need to update the model in realtime, since there are outlines, structure navigators, etc. that I know you have to keep in sync. Regardless, it's getting in the way of my editing, so hopefully there's a solution. I type pretty fast sometimes, and my intuition tells me that my fingers are outrunning something that the editor is trying to do, but I'm just guessing. What do you think?