Unity has reverted my particle systems from Shuriken to Legacy -- WHY?

This is bizarre! My Unity app was working fine, it has a game object with an attached script that starts:

[ RequireComponent( typeof( ParticleSystem ) ) ]

It goes on to trace a sine wave using 100 particles.

A few days back I created the script, dropped it on to the game object, instantly a Shuriken particle system component was added to the game object. It ran in the unity editor and deployed to my iPad. Great!

At some point this morning, Unity has flipped. now when I look at my game object, I see that the attached particle system component is no longer a Shuriken particle system. It is now a legacy particle system.

I create a fresh game object and drop the script onto it. Again, legacy particle system.

I create a fresh game object and attach a particle system component from the menu. Again, legacy particle system.

This morning, while this happened, I was working on an iOS plug-in. So I’m also using Xcode which has a project at /MyUnityProj/XCodeDummyProjForEditingObjCFiles/ which contains a group linking to /MyUnityProj/Assets/Plugins/iOS/ which contain half a dozen .h and .m ObjC files.

So I’m wondering whether some project setting could possibly have been corrupted due to manipulating files outside of the project inspector. But that sounds really far-fetched.

What on earth is happening?

EDIT: I just created a fresh project, created a game object. Already something is wrong. The way the transform is shown in the Inspector is different. Now I add a particle system. I get this:

This is wrong. That transform should be showing X Y Z boxes next to each other. Something is broken!

EDIT2: I’m using Unity 3.5.6 OSX

Classic case of me being an idiot. I had switched the Inspector to DEBUG view for a completely different task. Right clicking and switching back sorted it out.