[Unity 3.5.7] Crash involving GUIManager::SendQueuedEvents?

Code (csharp):

1. ========== OUTPUTING STACK TRACE ==================
2.  
3. (0x7361656C) (dbghelp): (filename not available): MiniDumpWriteDump
4. (0x005699DC) c:\buildagent\work\14194e8ce88cdf47\runtime\misc\guimanager.cpp (152): GUIManager::SendQueuedEvents
5. (0x00613B3D) c:\buildagent\work\14194e8ce88cdf47\platformdependent\winplayer\winmain.cpp (150): PerformMainLoop
6. (0x00614081) c:\buildagent\work\14194e8ce88cdf47\platformdependent\winplayer\winmain.cpp (371): MainMessageLoop
7. (0x006150D2) c:\buildagent\work\14194e8ce88cdf47\platformdependent\winplayer\winmain.cpp (728): WinMain
8. (0x00989FEF) f:\dd\vctools\crt_bld\self_x86\crt\src\crt0.c (263): __tmainCRTStartup
9. (0x770F3677) (kernel32): (filename not available): BaseThreadInitThunk
10. (0x77C6C002) (ntdll): (filename not available): RtlInitializeExceptionChain
11. (0x77C6BFD5) (ntdll): (filename not available): RtlInitializeExceptionChain
12.  
13. ========== END OF STACKTRACE ===========
14.  
15. **** Crash! ****

At some point recently we've started getting the above crash. We're trying to debug it now, but it's pretty difficult because the stack trace is as above - it's not clear which part of our code has caused this. What's more, the user behaviour used to recreate this has nothing to do with the GUI whatsoever - we've got a list of objects which they can load, and selecting any of those objects for a second time causes this crash. That selection is made via the GUI, of course, but the GUI doesn't do anything differently in that use case compared to selecting any object for the first time.

Has anyone seen this kind of thing before to be able to give us a pointer as to where this kind of thing might arise?

We're still using Unity 3.5.7 on this project because it's pretty big and relies on some of the stuff that changed in 4.0.

 

Solved.

We're not entirely sure what the issue was internally, but when I commented out our usage of GUIUtility.hotControl the issue stopped, so it was something related to that. Using a coroutine to delay the closing of the box and the resetting of the hotControl value to the end of the frame solved the issue.