You could try implementing the NSSplitView delegate method -splitViewDidResizeSubviews: to test whether the first subview (NSTableView and its scroll-view in this case) is collapsed (using -isSubviewCollapsed:), and if so then change an instance variable to store the scroll position ([[[tableView enclosingScrollView] verticalScroller] floatValue]), which you probably would have had to have gotten already in -splitViewWillResizeSubviews.
Whew. I hope that helps (and that it's the best method).
by Qwerty Denzel — Sep 30
You could try implementing the NSSplitView delegate method -splitViewDidResizeSubviews: to test whether the first subview (NSTableView and its scroll-view in this case) is collapsed (using -isSubviewCollapsed:), and if so then change an instance variable to store the scroll position ([[[tableView enclosingScrollView] verticalScroller] floatValue]), which you probably would have had to have gotten already in -splitViewWillResizeSubviews.
Whew. I hope that helps (and that it's the best method).