I can't tell what's happening on the lisp side here (I'm running a lot  
of code), but if you tell me what to look for, I will.
The build I'm using is very recent, with no patches to the redisplay  
code I believe.


Process:         Emacs [22516]
Path:            /Users/dr/Projects/Bazaar-Playground/emacs.cvs/ 
nextstep/Emacs.app/Contents/MacOS/Emacs
Identifier:      org.gnu.Emacs
Version:         Version 23.0.90 (9.0)
Code Type:       X86 (Native)
Parent Process:  launchd [137]

Date/Time:       2009-02-24 23:15:27.317 -0500
OS Version:      Mac OS X 10.5.6 (9G55)
Report Version:  6

Exception Type:  EXC_BREAKPOINT (SIGABRT)
Exception Codes: 0x0000000000000002, 0x0000000000000000
Crashed Thread:  0

Application Specific Information:
*** Terminating app due to uncaught exception  
'NSInternalInconsistencyException', reason: '-[EmacsView(0xe87e430)  
lockFocus] failed with window=0xe892b90, windowNumber=-1, [self  
isHiddenOrHasHiddenAncestor]=0'

Thread 0 Crashed:
0   libSystem.B.dylib             	0x9469ce42 __kill + 10
1   org.gnu.Emacs                 	0x000925da fatal_error_signal + 314  
(emacs.c:404)
2   libSystem.B.dylib             	0x9469b2bb _sigtramp + 43
3   ???                           	0xffffffff 0 + 4294967295
4   libSystem.B.dylib             	0x9470f23a raise + 26
5   libSystem.B.dylib             	0x9471b679 abort + 73
6   org.gnu.Emacs                 	0x0016cc45 ns_term_shutdown + 117  
(nsterm.m:4048)
7   org.gnu.Emacs                 	0x0009262f fatal_error_signal + 399  
(emacs.c:389)
8   libSystem.B.dylib             	0x9469b2bb _sigtramp + 43
9   ???                           	0xffffffff 0 + 4294967295
10  libobjc.A.dylib               	0x9499ae3b objc_exception_throw + 40
11  com.apple.CoreFoundation      	0x95774eeb +[NSException  
raise:format:arguments:] + 155
12  com.apple.Foundation          	0x94b8f6a4 -[NSAssertionHandler  
handleFailureInMethod:object:file:lineNumber:description:] + 116
13  com.apple.AppKit              	0x90106a0f -[NSView lockFocus] + 280
14  org.gnu.Emacs                 	0x00167560 ns_update_begin + 48  
(nsterm.m:563)
15  org.gnu.Emacs                 	0x00006d5c Fredraw_frame + 124  
(dispnew.c:3395)
16  org.gnu.Emacs                 	0x0010a4d1 Ffuncall + 977 (eval.c: 
3050)
17  org.gnu.Emacs                 	0x001456db Fbyte_code + 3835  
(bytecode.c:678)
18  org.gnu.Emacs                 	0x00109d81 funcall_lambda + 209  
(eval.c:3236)
19  org.gnu.Emacs                 	0x0010a049 apply_lambda + 121  
(eval.c:3155)