Popper briefly flickers in top left on initial show if no animation is used

[kybishop]

sigh This is because we're placing the popper in the top left to avoid initial positioning errors that would place the popper outside of the screen. The issue was hidden from me because I've always been using animations, which typically keep the popper invisible to the human eye until it has already been positioned appropriately.

I have a workaround in mind that uses visibility: hidden until the popper's first correct placement.

Temporary workaround: use the fade animation with a super short showDuration... just long enough to hide it for that initial flicker.