@James B the tabs still respond. is this the expected behavior?
Disabled tabs aren't really a user friendly thing. Here's from the Apple HIG about iOS tab bars (I was looking for desktop information, but I think the idea still applies).
Don’t remove or disable a tab when its function is unavailable.
If tabs are available in some cases but not in others, your app’s interface becomes unstable and unpredictable. Ensure that all tabs are always enabled, and explain why a tab’s content is unavailable. For example, if there are no songs on an iOS device, the My Music tab in the Music app explains how to download songs.
Even if you're not trying to explain how to download songs, the tab should still be selectable with the interface indicating there is nothing to do. This allows an app to be explored and understood prior to actual usage, which helps ease learning curves and improves user experience.