extendedFAB broken in IE11

[koshea]

• This is a v1.x issue (v0.x is no longer maintained).
• I have searched the issues of this repository and believe that this is not a duplicate.

Expected Behavior

The extendedFAB button should display normally in IE 11.

Current Behavior

Only the icon displays, the text is cut off. It appears this is because IE 11 does not support width: initial. I was able to fix it in my application by overriding that to width: auto but I am not sure if that is a perfect solution.

Steps to Reproduce (for bugs)

1. View the page at https://material-ui.com/demos/buttons/ and see the Extended FAB example. Screenshot attached.

Context

Your Environment

Tech	Version
Material-UI	v1.3.1
React
browser	IE11
etc

[oliviertassinari]

@koshea Thanks for raising the issue! The issue comes from this line:
https://github.com/mui-org/material-ui/blob/355317fb479dc234c6b1e374428578717b91bdc0/packages/material-ui/src/Button/Button.js#L138
IE11 doesn't support the initial value. So we need to set the initial value ourselves: auto.

Do you want to work on a pull request? :)

[koshea]

Sure, I found one other instance in core that uses initial and created a pull request #12199