This is bug documented in http://support.microsoft.com/kb/2531482. To fix the issue, we need to upgrade the SSMS to at least CU7.
Unlike SQL Server 2012 onward, there is separate binary for SSMS, SSMS 2008R2 is part of SQL server binary distribution. Therefore, what we need is the latest CU/SP for the core database engine.
As this post, the latest SQL Server 2008R2 service pack is SP3 release on 9/26/2014. This can be download from here.
RTM version of SSMS 2008R2
After the upgrade