diff --git a/browser/devtools/highlighter/inspector.jsm b/browser/devtools/highlighter/inspector.jsm
index 31219064ca5a..4498e60a4589 100644
--- a/browser/devtools/highlighter/inspector.jsm
+++ b/browser/devtools/highlighter/inspector.jsm
@@ -1247,6 +1247,10 @@ InspectorUI.prototype = {
       if (computed) {
         computed.parentNode.removeChild(computed);
       }
+      let autosizer = node.querySelector(".autosizer");
+      if (autosizer) {
+        autosizer.parentNode.removeChild(autosizer);
+      }
     }
 
     let text = node.textContent;
diff --git a/browser/devtools/styleinspector/CssRuleView.jsm b/browser/devtools/styleinspector/CssRuleView.jsm
index 8454afa5249e..179708e87030 100644
--- a/browser/devtools/styleinspector/CssRuleView.jsm
+++ b/browser/devtools/styleinspector/CssRuleView.jsm
@@ -1375,6 +1375,7 @@ InplaceEditor.prototype = {
     // up to the client), and b) without tweaking the style of the
     // original element, it might wrap differently or something.
     this._measurement = this.doc.createElementNS(HTML_NS, "span");
+    this._measurement.className = "autosizer";
     this.elt.parentNode.appendChild(this._measurement);
     let style = this._measurement.style;
     style.visibility = "hidden";