Great post you should read before stealing content...
Don't still create more content!
One more reminder from my older post
Monday, September 24, 2012
Sunday, September 2, 2012
, Or in many more other blogs.
This post is about setDefaultView and when it is not working.
Apparently when Lookup field parameter "View Selector" is set to off setDefaultView is not working.
You can read about it in this Microsoft form thread http://social.microsoft.com/Forums/en/crmdevelopment/thread/c36f4be5-9a26-4c04-9046-92d6f47b8e7a
There is a trick (Unsupported) to
Set the attribute control "disableViewPicker" to false and back to true after the default view is set.
For example and more details read the form thread.
Thank you yogi 4.0 for asking the right question and finding the answer you've saved me time here.