Drag n Drop re-ordering inconsistant

When I add a new video to a Gallery, it doesn’t always appear in the same place. I’d like a setting where it could default to the top or bottom of the list.

Then when I proceed to drag it into the top position, then look at the page on the site, it’s not at the top. It may be in the 2nd position or randomly further down the list, even though the admin shows it at the top. I usually have to move the 1st 2 in the list back and forth and couple of times before it actually appears correctly.