Scroll bar freezes with demo code

[BorntraegerMarc]

Description

When adding the following code:

    <paper-menu-button>
          <paper-icon-button icon="menu" slot="dropdown-trigger"></paper-icon-button>
     </paper-menu-button>

And click on the button I get this warning in the console:

Couldnt play ( fade-in-animation ). ReferenceError: KeyframeEffect is not defined
    at HTMLElement.configure (fade-in-animation.html:39)
    at HTMLElement._configureAnimations (neon-animation-runner-behavior.html:33)
    at HTMLElement.playAnimation (neon-animation-runner-behavior.html:93)
    at HTMLElement._renderOpened (iron-dropdown.html:233)
    at HTMLElement.__openedChanged (iron-overlay-behavior.html:541)

And the whole page freezes.

Expected outcome

No error

Actual outcome

Live Demo

Steps to reproduce

Browsers Affected

• [ X] Chrome
• [ X] Firefox
• [ X] Safari 9
• [ X] Safari 8
• [ X] Safari 7
• [ X] Edge
• [ X] IE 11
• [ X] IE 10

[BorntraegerMarc]

When I add the polyfill <link rel="import" href="assets/bower_components/neon-animation/web-animations.html"> Then I do not get a warning any more but the error still persists. I can not scroll anymore on the whole page

[jsilvermist]

+1, seeing the same scroll issue when using paper-swatch-picker, after opening it once I can no longer scroll the document. (Not related to animation error)