6.1.1 CE GA2, 6.1.20 EE GA2
Steps to reproduce:
1. Add a message board in a page, set the Scope as Select Page through configuration
2. Add a Search portlet
3. a) Selecting "Everything", click search
b) Selecting "This Site", click search
Search function works fine for Everything, but not for This Site
The situation is the same to "Documents and Media" portlet.