diff --git a/src/HtmlUtils.js b/src/HtmlUtils.js
index 5e8cfc3755..aec32092ed 100644
--- a/src/HtmlUtils.js
+++ b/src/HtmlUtils.js
@@ -365,6 +365,11 @@ export function bodyToHtml(content, highlights, opts) {
 }
 
 function addCodeCopyButton(safeBody) {
+    // Adds 'copy' buttons to pre blocks
+    // Note that this only manipulates the markup to add the buttons:
+    // we need to add the event handlers once the nodes are in the DOM
+    // since we can't save functions in the markup.
+    // This is done in TextualBody
     const el = document.createElement("div");
     el.innerHTML = safeBody;
     const codeBlocks = Array.from(el.getElementsByTagName("pre"));
diff --git a/src/components/views/messages/TextualBody.js b/src/components/views/messages/TextualBody.js
index 45fca566b9..d5a1977cdd 100644
--- a/src/components/views/messages/TextualBody.js
+++ b/src/components/views/messages/TextualBody.js
@@ -94,14 +94,13 @@ module.exports = React.createClass({
                     }
                 }, 10);
             }
+            // add event handlers to the 'copy code' buttons
             const buttons = ReactDOM.findDOMNode(this).getElementsByClassName("mx_EventTile_copyButton");
-            if (buttons.length > 0) {
-                for (let i = 0; i < buttons.length; i++) {
-                    buttons[i].onclick = (e) => {
-                        const copyCode = buttons[i].parentNode.getElementsByTagName("code")[0];
-                        this.copyToClipboard(copyCode.textContent);
-                    };
-                }
+            for (let i = 0; i < buttons.length; i++) {
+                buttons[i].onclick = (e) => {
+                    const copyCode = buttons[i].parentNode.getElementsByTagName("code")[0];
+                    this.copyToClipboard(copyCode.textContent);
+                };
             }
         }
     },