I have also got in a similar bug in Tiger. But closing the project drawer and reopening usually fixes it.
On 4-Nov-07, at 2:46 PM, Allan Odgaard wrote:
This is the third time I hear someone experience this, so something likely broke in Leopard. It would however (with 99.9% certainty) be an OS bug, so best to report at at http://bugreport.apple.com