Position fixed and ripple effect

MDL version: 1.3
Browser: Chrome
Browser version: 48.0.2564.109 (64-bit)
Operating system: ubuntu
Operating system version: 14.04 LTS
URL: na

I'm working with a design where I have a mdl-card with toolbar buttons placed in a footer. The buttons are "decorated" with ripple effect. In some cases, the footer may be sticky and placed at the bottom of the viewport. The problem that arises when the footer is sticky is that the footer disappears while ripple animation is in progress. This is not a big problem since I can remove ripple effect to avoid this - but I think it might be okay for you to verify this.

What steps will reproduce the problem:
1. Code a mdl-card
2. Add a footer element with position fixed inside mdl-card
3. Inside the footer code a nav element with buttons decorated withclass"mdl-js-ripple-effect"
4: Click on the button

What is the expected result?
The ripple effect should work the same as when footer has position absolute

What happens instead of that?
The footer disappears while ripple animation is in progress.

Please provide any other information below, and attach a screenshot if possible.

Example code to reproduce issue:

``` html

Material Design Lite Extensions

.mdl-card {
position: relative;
}
footer {
display: flex;
justify-content: space-between;
align-items: center;
width: 100%;
padding: 8px;
background-color: #FFFFFF;
position: absolute;
bottom: 0;
left: 0;
}
footer.sticky--footer {
position: fixed;
}
footer .mdl-card__supporting-text {
flex: 1;
overflow: hidden;
padding: 0;
height: 16px;
width: 100%;
}

```