Fixed #3904 - Panel: Header accessibility issue

components/lib/panel/Panel.d.ts

@@ -137,7 +137,16 @@ export interface PanelSlots {
     /**
      * Custom header template.
      */
-    header(): VNode[];
+    header(scope: {
+        /**
+         * Current id state as a string
+         */
+        id: boolean;
+        /**
+         * Style class of the icon
+         */
+        class: string;
+    }): VNode[];
     /**
      * Custom icons template.
      */

components/lib/panel/Panel.vue

@@ -1,7 +1,7 @@
 <template>
     <div :class="containerClass" v-bind="ptm('root')">
         <div class="p-panel-header" v-bind="ptm('header')">
-            <slot name="header">
+            <slot :id="ariaId + '_header'" name="header" class="p-panel-title">
                 <span v-if="header" :id="ariaId + '_header'" class="p-panel-title" v-bind="ptm('title')">{{ header }}</span>
             </slot>
             <div class="p-panel-icons" v-bind="ptm('icons')">