Lion apparently objects to this line:
impl->toplevel = [impl->toplevel initWithContentRect:rect
                                           styleMask:new_mask
                                             backing:NSBackingStoreBuffered
                                               defer:NO];
Replacing it with a simple
[impl->toplevel];
impl->toplevel = [[GdkQuartWindow alloc] initWithContentRect:rect
                                           styleMask:new_mask
                                             backing:NSBackingStoreBuffered
                                               defer:NO];

eliminates the crash and appears to solve the problem.

[impl->toplevel release];
impl->toplevel = [[GdkNSWindow alloc] initWithContentRect...] instead.
 
Although investigated in 2.24, the code is unchanged in master (except that instead of calling GdkQuartzWindow it needs to be GdkQuartzNSWindow). There's no reason to believe the problem doesn't also exist there.


(gdb) bt f

+ Trace 227838