diff --git a/Rakefile b/Rakefile
index 8694104..ed29cdb 100644
--- a/Rakefile
+++ b/Rakefile
@@ -3,5 +3,5 @@ require "html/proofer"
 task :test do
   sh "bundle exec jekyll build --trace"
   # ignore href="#" for the "Copy to clipboard" button
-  HTML::Proofer.new("./_site", :href_ignore => ["#"]).run
+  HTML::Proofer.new("./_site").run
 end
diff --git a/_includes/sidebar.html b/_includes/sidebar.html
index f62639e..dedb0e0 100644
--- a/_includes/sidebar.html
+++ b/_includes/sidebar.html
@@ -1,6 +1,6 @@
 <div class="sidebar">
 
-  <a href="#" data-clipboard-target="license-text" class="js-clipboard-button button">Copy license text to clipboard</a>
+  <a href="#" data-clipboard-target="license-text" data-proofer-ignore="true" class="js-clipboard-button button">Copy license text to clipboard</a>
   <div class="how-to-apply">
     <h5>How to apply this license</h5>
     <p>