It’s a little disconcerting that rebuilding a Cocoa application changes its behavior. For example, Opal’s Export as command used
NSExportableAsto specify the possible types. Under Leopard, this requires the use of UTIs, which Opal didn’t use. So Export as (which worked fine in Leopard) broke as soon as I rebuilt. Another change was the preview pane in Print dialogs. This showed up only after I rebuilt in Leopard. That was cool, new behavior for free! Except it wasn’t quite right. So I had to figure out how to hook Opal’s print dialog controls so that they updated the preview. Bottom line: an application that works fine in Tiger may require significant work as soon as you touch it under Leopard.
I haven’t seen anything similar in the Carbon world (which GameHouse games use).