Fixes #2444: Pressing down on URL bar should open autosuggest

[willy-b]

• Used Github auto-closing keywords in the commit message.

[willy-b]

Oops, it looks like some checks have failed.
However, the AppVeyor errors seem to be in an early part of the build process (npm preinstall/install ; installing bloom-filter-cpp?) which was not modified. I didn't change any dependencies, so confused how the 'npm install' step got broken.

See below:

[bbondy]

We don't have AppVeyor fully setup yet so you can ignore that. Also Travis will intermittently fail so no worries there.

[willy-b]

OK, consistent with that, the Travis test failures are all timeouts:

I'll still look into those tests locally and see if these timeouts might be reflecting a UI slowdown from the changes.

[bbondy]

This is a little different behaviour than what I was expecting and what chrome/firefox does.
Could you only show when there is an onKeyDown event?

[willy-b]

Whoops, thought the issue was asking for dropdown on mouse-down! Fixed now :-).

[bbondy]

perfect, thanks for the patch!