list window does not disapper of Obout ComboBox control

I am developing a web application. I used ajax Update panel & under update panel I used gridview for displaying data. In gridviews edit template I used three Obout ComboBox Control(third party) and bind the data from database.for moving one control to another controls I am using tab key.I used tab key from one combobox its move on second combobox when its move then it is displaying list window of combobox it wont disappear after I go to next control and also when I save the data it well display list of comboxBox.

For example of marked comboBox I attached two images 1)”” when I move one comboBox to another comboBox it is displaying list 2)”” when I save the data it is displaying list window of comboBox. But when I remove the update panel it won't display such list after focus is moved.

Note:When I use mouse to move one comboBox to another comboBox, list window of ComboBox wont come on screen.

VS:2010 Code-Behind:VB.net Obout Suite Version:3.5

using obout comboBox property openOnfoucs="false" , solved the problem. It does not display list window when focus moved to another control.