Edited Unassigned: Pressing Enter Key on Selecting Item in ComboBox Causes Postback [28012]

Hi,

I am using Ajax Control toolkit version 15.1.4 on my Webform. On Chrome browser ( version 47.0.2526.106 m ), when I open the page and selecting item in combobox and pressing enter key, it causes the page to postback.

However, the same page open on firefox, it does not postback the page on pressing enter key.

How to prevent the postback on chrome browser during selecting the combobox's item and pressing enter key.

Please help.

Thanks & Regards
Hatim