I can't change the priority field when filing a bug for a failure. When I hit the File Bug button, a dialog pops up. When I click the priority field, a select menu shows. However, when I click an entry in the menu, nothing happens. When I click the P2 field again, the whole dialog disappears.

Url: https://sheriff-o-matic.appspot.com/android

There's a JS error in the console:
Uncaught ReferenceError: KeyframeEffect is not defined
    at HTMLElement.configure (som-app.vulcanized.html:31284)
    at HTMLElement._configureAnimations (som-app.vulcanized.html:26870)
    at HTMLElement.playAnimation (som-app.vulcanized.html:26940)
    at HTMLElement._renderOpened (som-app.vulcanized.html:35227)
    at HTMLElement.__openedChanged (som-app.vulcanized.html:29358)
    at HTMLElement.nextAnimationFrame (som-app.vulcanized.html:29381)