(fix:widget: Keep a back-button entry while any panel is open

extensions/react-widget/src/hooks/useBackDismiss.ts

@@ -6,15 +6,33 @@ const HISTORY_MARKER = 'dgptOverlay';
 const layers: Array<() => void> = [];
 let entryPushed = false;
 let releaseTimer: ReturnType<typeof setTimeout> | 0 = 0;
+let releasing = false;
 
 const ours = () =>
   (window.history.state as Record<string, unknown> | null)?.[HISTORY_MARKER] ===
   true;
 
+const arm = () => {
+  if (entryPushed) return;
+  entryPushed = true;
+  if (!ours()) window.history.pushState({ [HISTORY_MARKER]: true }, '');
+  window.addEventListener('popstate', handlePopState);
+};
+
 const handlePopState = () => {
+  if (releasing) {
+    releasing = false;
+    entryPushed = ours();
+    if (layers.length > 0) arm();
+    else if (!entryPushed)
+      window.removeEventListener('popstate', handlePopState);
+    return;
+  }
   // A host entry stacked above ours pops first, leaving ours in place.
   entryPushed = ours();
+  const remaining = layers.length > 1;
   layers[layers.length - 1]?.();
+  if (remaining) arm();
 };
 
 const register = (dismiss: () => void) => {
@@ -23,10 +41,7 @@ const register = (dismiss: () => void) => {
     clearTimeout(releaseTimer);
     releaseTimer = 0;
   }
-  if (entryPushed) return;
-  entryPushed = true;
-  window.history.pushState({ [HISTORY_MARKER]: true }, '');
-  window.addEventListener('popstate', handlePopState);
+  arm();
 };
 
 const unregister = (dismiss: () => void) => {
@@ -38,11 +53,14 @@ const unregister = (dismiss: () => void) => {
   releaseTimer = setTimeout(() => {
     releaseTimer = 0;
     if (layers.length > 0) return;
-    window.removeEventListener('popstate', handlePopState);
-    if (!entryPushed) return;
     entryPushed = false;
     // Closing by button or overlay would otherwise leave the entry behind.
-    if (ours()) window.history.back();
+    if (ours()) {
+      releasing = true;
+      window.history.back();
+      return;
+    }
+    window.removeEventListener('popstate', handlePopState);
   });
 };