Currently, all my angular material HTML attributes are highlighted in yellow with WebStorm 9 (Mac OS X Yosemite) warning: \"Attribute [name] is not allowed here\".
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I am using PHPStorm, which is a sister Project of WebStorm, but it should work the same way.
You maybe need to add the Library:

Add here AngularJS
If this does not work, you can add them manually:

Follow this Steps:
To the right you will see in Options "Custom HTML tag attributes". Enter here the attributes you want to allow.