Dropdown closing on mousedown instead of mouseup

Created by: miguelmich

I noticed in the last release (v4.0.0-alpha.6) a new dropdown behavior was introduced, my question is: is this new behavior intentional? because the new interaction seems to be a little odd compared with the old one (closing dropdowns on mouseup).

Testing on Google Chrome Version 55.0.2883.87 (64-bit), Linux Ubuntu Gnome