diff --git a/webpack.config.js b/webpack.config.js
index c2fd7a8..da29d0c 100755
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -186,6 +186,7 @@ function getCSSWhitelistPatterns() {
     /^body$/,
     /^figure$/,
     /^blockquote$/,
+    /^is-active$/,
     /^collapse$/,
     /^collapsing$/,
     /^label$/,