Hi Hristo,
Thank you so much, your proposed example is extremely helpful (especially the amazing ‘optimal’ function). Here is my modification based on your solution. So now, final width can be calculated on ‘open’ event, and the result is just what I wanted. At least this gonna be a solution protoype to be enhanced later. You see, I set the {autoDropDownHeight: false}, since I don’t want the scroll-bar to appear on document.body part.
Wow,,, one more thing to solve. Now, while the vertical scroll-bar stays intact, how to calculate the height of dropdown window to it’s maximum without exceeding bottom edge of viewport when the returned data item is quite many (say:300 items)?….