As of the latest Chrome - sigh - they have changed something along with their default scroll look - which I don't really like... anyway, it is causing the down arrow to scroll sometimes when we try and resize. Will see if we can fix that up somehow. The update initially broke the resize, we could not grab the handle. So we put the handle at a higher z-index and that solved it but now both work.
Sort of at a loss on how to fix it aside from shortening the height of the frame which would leave an unused space under it - which is not optimal. Maybe put something above the iframe in the at corner with low opacity and block the mouse hitting the scroll arrow - don't really care if they can't press the arrow - it is not often needed.