Clean Build Folder option disabled in Xcode 5

Question

I have an iOS project that builds and runs fine, but the "Clean Build Folder..." option is disabled. As a matter of fact, it is disabled in all of my projects (all iOS, some in workspaces).

They have not been upgraded from previous Xcode version as discussed in this thread.

To See the Clean Build Folder... option, hold the option key while viewing the Product menu.

What can I do to enable it?

Update:

Almost a year later. Currently on Xcode 6.3. Still no luck.

Answer 1

I tried the following steps. Preference --> Locations --> For derived data, click "Advanced". Inside build location, choose "Unique". The "Clear Build Folder" button appears again.