Have tried the autoquit suggestion but result is the same.
Notice that this is a test app with only one window and a combo box, the window open fills the combo and the combo chnge event quits or closes, nothing else in the app.
Follows a copy of the crash report, this is after running in debug mode:
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Exception Type: EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000000000004
VM Regions Near 0x4:
–> __PAGEZERO 0000000000000000-0000000000001000 [ 4K] —/--- SM=NUL /var/folders//test.debug.app/Contents/MacOS/test.debug
__TEXT 0000000000001000-000000000017a000 [ 1508K] r-x/rwx SM=COW /var/folders//test.debug.app/Contents/MacOS/test.debug
Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 com.apple.AppKit 0x900db21b -[NSView focusRingType] + 9
1 com.apple.AppKit 0x900db202 -[NSControl focusRingType] + 92
2 com.apple.AppKit 0x900db105 -[NSView(NSInternal) _effectiveFocusRingType] + 35
3 com.apple.AppKit 0x902de2e3 -[NSView _setKeyboardFocusRingNeedsDisplayInRect:force:] + 45
4 com.apple.AppKit 0x902de2ae -[NSView setKeyboardFocusRingNeedsDisplayInRect:] + 63
5 com.apple.AppKit 0x904f22ea -[NSComboBoxCell trackMouse:inRect:ofView:untilMouseUp:] + 601
6 com.apple.AppKit 0x904ef0c1 -[NSComboBox mouseDown:] + 315
7 rbframework.dylib 0x002e0830 0x1c5000 + 1161264
8 com.apple.AppKit 0x90291e4d -[NSWindow sendEvent:] + 11953
9 rbframework.dylib 0x002eeccc 0x1c5000 + 1219788
10 com.apple.AppKit 0x9022dcad -[NSApplication sendEvent:] + 4034
11 rbframework.dylib 0x002be3e4 0x1c5000 + 1020900
12 rbframework.dylib 0x002be430 0x1c5000 + 1020976
13 test.debug 0x00002bf3 Delegate.Invoke%% + 34
14 test.debug 0x0007d6ec Application._CallFunctionWithExceptionHandling%%op + 264
15 rbframework.dylib 0x00244a50 0x1c5000 + 522832
16 rbframework.dylib 0x002be355 0x1c5000 + 1020757
17 com.apple.AppKit 0x900723bc -[NSApplication run] + 823
18 rbframework.dylib 0x00244ad7 0x1c5000 + 522967
19 rbframework.dylib 0x002178e1 RuntimeRun + 49
20 test.debug 0x00131585 REALbasic._RuntimeRun + 34
21 test.debug 0x00002adf _Main + 257
22 test.debug 0x000024f0 % main + 36
23 test.debug 0x0016b190 _start + 116
24 test.debug 0x0016b0e6 start + 43
Thread 1:: Dispatch queue: com.apple.libdispatch-manager
0 libsystem_kernel.dylib 0x96d6e992 kevent64 + 10
1 libdispatch.dylib 0x973df8bd _dispatch_mgr_invoke + 238
2 libdispatch.dylib 0x973df556 _dispatch_mgr_thread + 52
Thread 2:
0 libsystem_kernel.dylib 0x96d6e046 __workq_kernreturn + 10
1 libsystem_pthread.dylib 0x99387dcf _pthread_wqthread + 372
2 libsystem_pthread.dylib 0x9938bcce start_wqthread + 30
Thread 3:
0 libsystem_kernel.dylib 0x96d6e046 __workq_kernreturn + 10
1 libsystem_pthread.dylib 0x99387dcf _pthread_wqthread + 372
2 libsystem_pthread.dylib 0x9938bcce start_wqthread + 30
Thread 4:
0 libsystem_kernel.dylib 0x96d6e046 __workq_kernreturn + 10
1 libsystem_pthread.dylib 0x99387dcf _pthread_wqthread + 372
2 libsystem_pthread.dylib 0x9938bcce start_wqthread + 30
Thread 5:
0 libsystem_kernel.dylib 0x96d68f7a mach_msg_trap + 10
1 libsystem_kernel.dylib 0x96d6816c mach_msg + 68
2 com.apple.CoreFoundation 0x9363af69 __CFRunLoopServiceMachPort + 169
3 com.apple.CoreFoundation 0x9363a541 __CFRunLoopRun + 1393
4 com.apple.CoreFoundation 0x93639d5a CFRunLoopRunSpecific + 394
5 com.apple.CoreFoundation 0x93639bbb CFRunLoopRunInMode + 123
6 com.apple.AppKit 0x90229f18 _NSEventThread + 283
7 libsystem_pthread.dylib 0x993865fb _pthread_body + 144
8 libsystem_pthread.dylib 0x99386485 _pthread_start + 130
9 libsystem_pthread.dylib 0x9938bcf2 thread_start + 34
Thread 0 crashed with X86 Thread State (32-bit):
eax: 0x00000000 ebx: 0x0054bf00 ecx: 0x90b401f5 edx: 0x00000000
edi: 0x0054bf00 esi: 0x900db1b3 ebp: 0xbffff2a8 esp: 0xbffff2a8
ss: 0x00000023 efl: 0x00010246 eip: 0x900db21b cs: 0x0000001b
ds: 0x00000023 es: 0x00000023 fs: 0x00000000 gs: 0x0000000f