diff --git a/addon/chrome/content/lib/css/copy-tex.css b/addon/chrome/content/lib/css/copy-tex.css
deleted file mode 100644
index 6999c63..0000000
--- a/addon/chrome/content/lib/css/copy-tex.css
+++ /dev/null
@@ -1,13 +0,0 @@
-/* Force selection of entire .katex/.katex-display blocks, so that we can
- * copy/paste the entire source code.  If you omit this CSS, partial
- * selections of a formula will work, but will copy the ugly HTML
- * representation instead of the LaTeX source code.  (Full selections will
- * still produce the LaTeX source code.)
- */
-.katex,
-.katex-display {
-    -webkit-user-select: all;
-       -moz-user-select: all;
-            user-select: all;
-}
-