diff --git a/devtools/client/inspector/boxmodel/box-model.js b/devtools/client/inspector/boxmodel/box-model.js
index d1fb7a217044..785cb5b96f76 100644
--- a/devtools/client/inspector/boxmodel/box-model.js
+++ b/devtools/client/inspector/boxmodel/box-model.js
@@ -233,6 +233,11 @@ BoxModel.prototype = {
    * Hides the box-model highlighter on the currently selected element.
    */
   onHideBoxModelHighlighter() {
+    // As React components aren't destroyed when the panel closes,
+    // this function may still be called and throw because of destroyed fronts.
+    if (!this.inspector) {
+      return;
+    }
     this.inspector.highlighters.hideHighlighterType(
       this.inspector.highlighters.TYPES.BOXMODEL
     );
diff --git a/devtools/client/inspector/inspector.js b/devtools/client/inspector/inspector.js
index 9e81c81bfffe..8dbed0e2b8e1 100644
--- a/devtools/client/inspector/inspector.js
+++ b/devtools/client/inspector/inspector.js
@@ -1927,6 +1927,11 @@ Inspector.prototype = {
    *         Options passed to the highlighter actor.
    */
   onShowBoxModelHighlighterForNode(nodeFront, options) {
+    // As React components aren't destroyed when the panel closes,
+    // this function may still be called and throw because of destroyed fronts.
+    if (this._destroyed) {
+      return;
+    }
     this.highlighters.showHighlighterTypeForNode(
       this.highlighters.TYPES.BOXMODEL,
       nodeFront,