How can I fix WebStorm warning “Unresolved function or method” for “require” (Firefox Add-on SDK)

I’m using WebStorm 7 for Firefox Add-on SDK development.

WebStorm shows a warning: “Unresolved function or method” for require().

I want to get rid of the warning.

var pageMod = require("sdk/page-mod");

NOTE:I already configured JavaScript-library (refer /lib/sdk globals).

Environment:

• WebStorm 7.0.2
• Windows 7 64bit
• Firefox Add-on SDK 1.15beta1