I have list of services (Object) in my grid. I've added a record (Services Object) on different page. Then, refresh the grid when I came to Grid page. I have got the error below.

An error occurred while refreshing the data from field 'Services.unitset_id' to property 'SelectedValue' on control 'editUnitSet.'

When I open the page from menu. I have seen the added record.

Any Comment ?

I have not had a change to look at this in depth.  I tried to re-produce the problem quickly, but had no issues.  Since I am going to have to take your code and try and reconstruct your issue, I have not had a chance to do this.  If you want to supply the sample, it may go faster.  But as of yet, I have not been able to reproduce nor have I spent an extended amount of time trying to reproduce since I couldn't reproduce it quickly.

So at present, this is on a list to look at, and it is something that we will try to look at prior to the final 1.6.6 build.  If you want to provide a sample showing the error versus just showing a code snippet, it will definitely speed up the process.