CSS initial value is unsupported in IE

[MarkFalconbridge]

There are a number of scss files that specify "initial" as a value for various properties. IE doesn't support the value "initial" - see http://caniuse.com/#search=initial. This can lead to unexpected behaviour because IE falls back to the next most appropriate css selector.

[crisbeto]

Could you give some examples where it breaks for you? We do use initial, but for the cases that I've seen, there's usually a fallback.

[MarkFalconbridge]

The instance I had to work around was when using md-list-item elements. When hovering over them I was getting an unexpected fallback for the <div class="md-button _md-no-style"> hover background-color. This was because elsewhere we had specified a different background-color for hovering on elements with the .md-button class so arguably, it's our problem because we've modified the .md-button class but it means you can get into an unusual fallback situation.

[clshortfuse]

Here's the usage of initial:

material/src/components/list/list.scss

Line 149 in 9a2c47d

background-color: initial;

I don't see the use of this CSS rule. .md-button doesn't normally have a background-color unless you add a class (md-primary, md-fab, etc). When it's generated in a list, it doesn't have any of those classes.

The issue stems from here: #7551

In this commit by @devversion: 9158589 background-color changed from from inherit to initial

But when tested on master, I removed the entire background-color rule and found no issue.

I think it can be safely removed.

[devversion]

@MarkFalconbridge That sounds reasonable.

We recently removed those fallback sequences so there shouldn't be that much properties with unsupported values. See 9a2c47d

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@clshortfuse Can you specifically file a short issue for the list item, so I can keep track of it?

[clshortfuse]

Found initial in tabs and filed an issue in #9223

I also found initial in

material/src/components/sidenav/sidenav.js

Line 374 in 82fdd2c

bottom: 'initial',

And this makes no sense:

material/docs/app/css/style.css

Line 190 in b9db09d

-ms-user-select: initial;

[crisbeto]

The last few should be taken care of with #9257