Xcode 4.2 simulator BUG ? works then doesn't

[MaxBodine]

I spent yesterday trying to writing 5 different apps with a tab bar controller. Every time I ran the the simulator it would show the demo on it.

I closed Xcode and the simulator trying to clear it out. Still didn't work.

I sat down this morning followed a simple tutorial on the tab bar. It worked. I knew I had done the same thing yesterday. I tried all 5 and they worked.

So I started writing the method, ran the simulator testing a couple of times as I went. All okay.

Then all of a sudden NONE of them work again. Now I didn't change any of the code in the others. I rebooted my computer. Still nothing.

Any ideas?