On Apr 30, 2013, at 00:39 , Gideon King <gid...@novamind.com> wrote:

> My scenario is a whole lot of sibling, potentially translucent, overlapping, 
> layer backed views.

I've never seen any evidence that sibling *NSView*s draw in the wrong order 
since 10.5. I believe that 'drawRect:' is correctly called in the back-to-front 
order of the sibling arrangement in the parent view.

However, I *have* seen firsthand, in the last few weeks, that the layers of 
siblings under a layer-backed parent view were composited in a random order. In 
my case, I had two sibling views, and I observed the bottom one displaying "on 
top" unpredictably, about 50% of the time.

To be clear, the layers didn't get re-ordered randomly every time they were 
drawn. The random order was baked into the view or layer hierarchy as part of 
the view initialization, and didn't change subsequently as long as the view 
existed.

So from my own experience, I'd agree there is a problem, but I don't know where 
the problem lies. It may be nothing to do with layers. Perhaps there's 
currently a bug loading nibs that randomly re-orders sibling views. Perhaps the 
sibling order in the layer hierarchy doesn't match the order in the view 
hierarchy. Perhaps the hierarchies are correct but the layer compositing 
operation is wrong.

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