The citation autocomplete preview disappears

I love the reference (cite} autocomplete feature in Texstudio. I use it all the time.
I also love the fact that it has a little preview which shows the details on each reference.

But, recently, the little preview window that shows the details of the references (the author, date, title etc) start to disappear immediately. It used to give me time to check the right reference by reading the titles.

Look at the following video to see the little preview disappearing immediately.

http://take.ms/2zDXr

Have anyone experienced the same problem?
(I have tried to delete the user profile, and tested different versions of Texstudio, with no avail).