Symptoms

We have a picker control connected to the AD User SmartObject.
The issue occurs when I hit the search window (so the pop-up appears) and then hit the search button without any parameter.
The search pop-up spears to get 'stuck' and does not exit the load animation.
 

Diagnoses

The client reported that the Identity.Identity table had over 9,000 entries and could be the cause of the issue.
 

Resolution

Initially I assumed it was an issue with the number of entries being returned.
I suggested adding parameters or filter properties to the picker control

The client resolved the issue with the following notes:

"Thanks for you efforts and help. Here is what I found the source of the issue to be (not with K2). The backing field for the value was varchar (not nvarchar) and yet data had been recently imported with unicode values (Korean Names apparently). The varchar field could not handle these. The error in the Application log was found which was along the lines of "Invalid character". This was the real clue.

For now we cleaned the offending values (this was a test DB anyway). But in future the lesson is to use nvarchar for corporate data so unicode characters are handled as expected".