Buttons get keyboard focus when tapped and also at random times

[n1ywb]

Description

FAB's get keyboard focus at weird times including

• randomly when tapped
• randomly when changing browser tabs

happens on desktop (chromium 53) and mobile (android chrome 53)

desktop (focus goes away if you click ANYWHERE in the browser window; even grabbing the screenshot removes it after the shot is taken)

mobile

http://imgur.com/aVH9g8T

Expected outcome

FAB should only acquire keyboard focus when the user tabs to it or maybe other times but not randomly

Actual outcome

fab acquires and loses keyboard focus and flashes to an ugly color when it happens

Live Demo

https://elements.polymer-project.org/elements/paper-fab?view=demo:demo/index.html&active=paper-fab

Steps to reproduce

1. open https://elements.polymer-project.org/elements/paper-fab?view=demo:demo/index.html&active=paper-fab
2. Open some more browser tabs
3. switch back to demo tab
4. switch to a different tab and back to demo tab until you see one of the buttons get focus (might take a few times)
5. Switch to another tab and back to demo tab and sometimes it loses keyboard focus, sometimes not

Second way:

1. open https://elements.polymer-project.org/elements/paper-fab?view=demo:demo/index.html&active=paper-fab
2. start responsive design mode
3. tap buttons until one of them starts to randomly acquire and lose keyboard focus when it is tapped

Browsers Affected

• [ X ] Chrome Version 54.0.2840.100 (64-bit)
• [ X ] Chromium 53 desktop
• [ X ] Chrome 53 android

[keanulee]

See also: https://github.com/PolymerElements/paper-button/issues/24