Frustratingly, it appears this is not fixed in the latest 5.8SP.
Omni folks, I expect you already know this, but just in case... in OWCompletionController you're missing a call to:
Code:
[completionWindow setCollectionBehavior:NSWindowCollectionBehaviorMoveToActiveSpace]
And yes, this was so annoying I actually traced it down and verified the fix.
Please consider fixing this in a 5.8SP soon and I can remove my private hack :)
Axxel