http://plnkr.co/edit/aNsDEC4BH42x9uay8ICJ?p=preview

Experiencing some strange behavior when using the keyboard to fire an md-button with an ng-click event. I only tested in Windows.

In Chrome/Windows
If you use the keyboard to tab to the button and hit the space bar to press the button, the ng-click event fires twice.

In Firefox/Windows
If you use the keyboard to tab to the button and hit the space bar to press the button, nothing happens (expected?). If you hit Return, nothing happens. But if you click the button after hitting Return, the ng-click event fires for every time you hit Return as though the event was being queued up.

In Internet Explorer/Windows
Similar to firefox, if you hit space, you see the button press but nothing happens until you click the button. Any previous button presses using the space bar appear.