diff --git a/lib/components/controls/custom.control.ts b/lib/components/controls/custom.control.ts
index 1f15d98..7df81bb 100644
--- a/lib/components/controls/custom.control.ts
+++ b/lib/components/controls/custom.control.ts
@@ -36,7 +36,7 @@ export default defineComponent({
      */
     class: {
       type: String as PropType<string>,
-      default: 'maplibregl-ctrl maplibregl-ctrl-group',
+      default: "maplibregl-ctrl maplibregl-ctrl-group",
     },
   },
   slots: Object as SlotsType<{ default: unknown }>,
diff --git a/lib/components/popup.component.ts b/lib/components/popup.component.ts
index dd3b872..47c2edd 100644
--- a/lib/components/popup.component.ts
+++ b/lib/components/popup.component.ts
@@ -172,6 +172,17 @@ export default defineComponent({
       () => props.maxWidth,
       (v) => popup.setMaxWidth(v),
     );
+    watch(
+      () => props.className,
+      (value, previous) => {
+        if (previous) {
+          popup.removeClassName(p);
+        }
+        if (value) {
+          popup.addClassName(v);
+        }
+      },
+    );
     watch(
       () => props.subpixelPositioning,
       (v) => popup.setSubpixelPositioning(v),