On Feb 19, 2019, at 3:57 AM, Jonathan Taylor <jonathan.taylor@...> wrote:
The problem is that as far as I can see this is something internal to AppKit, and I’m not sure what is triggering this problem. This is running on OS 10.9.5 (yes, sorry…), built using Xcode 6.2, with both deployment target and SDK set to 10.9. Can anyone suggest what the problem is, or what I might do to diagnose it further?
As Quincey said, it looks like you've got a zombie pointer that's now pointing to an NSWindowGraphicsContext instead of the original, now-deallocated NSSnapshotBitmapGraphicsContext.
Turn on zombie objects in Xcode. In newer versions of Xcode, it's in the Run > Diagnostics for the project's scheme. I'm trying to remember where this is in Xcode 6 - I _think_ you want to launch the app using Instruments and then use the Zombie module in Instruments.