I tried your reported experiment, and found that OmniFocus did exactly the correct thing in all cases. I would check to make sure that you've got the Restore Layout box ticked in all of your perspectives. The behavior you get if you've omitted it is like what you have described.
In any case, why should it matter if "restore layout" isn't checked for some of my perspectives? When I switch to one for which it *is* checked, *that* layout should surely be restored (regardless of the "restore layout" setting of the *previous* perspective), but this is clearly not what's happening -- at least not for me.
* By which I mean: whether the sidebar itself is collapsed or expanded. I realize this term is a little ambiguous since it normally refers to whether items in a list are "expanded" (showing child items).
Last edited by Stormchild; 2012-09-05 at 08:37 AM.. Reason: Clarification