>>Yes, I collapsed the region, but search was automatically expanding it. It is definitely a behavior change between VS 2008 and VS 2010.
>>
>>Quick search within options didn't find anything relevant.
>>
>>May be it's mentioned in "What's New" section of VS 2010?
>>
>>Try also googling on this problem.
>
>Ok, I wasn't sure if it was like that or not in VS 2008. But, if I brought it, there was a good chance I never experienced that in VS 2008. I will let you know about this research. I am pretty sure they would have come up with an option if they changed the behavior.

I see the same behavour in VS2008 and VS2010 (VB and C#) : If the search expression exists in a collapsed region then the region is expanded. Personally I'd think any other behaviour would be a nightmare - most of the time you would have to manually expand all collapsed regions prior to a search to be sure of not missing something.....