From 39eb6912527b54a610dade1a7072151ca373de77 Mon Sep 17 00:00:00 2001
From: Calixte Denizet <calixte.denizet@gmail.com>
Date: Wed, 22 Apr 2026 18:15:04 +0200
Subject: [PATCH] Fix status label mismatch after merging with a pre-existing
 selection (bug 2034111)

---
 test/integration/reorganize_pages_spec.mjs | 45 ++++++++++++++++++++++
 web/pdf_thumbnail_viewer.js                |  8 ++++
 2 files changed, 53 insertions(+)

diff --git a/test/integration/reorganize_pages_spec.mjs b/test/integration/reorganize_pages_spec.mjs
index 43d0f7de1..ab0a6aa4c 100644
--- a/test/integration/reorganize_pages_spec.mjs
+++ b/test/integration/reorganize_pages_spec.mjs
@@ -3123,5 +3123,50 @@ describe("Reorganize Pages View", () => {
         })
       );
     });
+
+    it("should show only merged pages as selected when a page was pre-selected (bug 2034111)", async () => {
+      await Promise.all(
+        pages.map(async ([browserName, page]) => {
+          await waitForThumbnailVisible(page, 1);
+
+          const labelSelector = "#viewsManagerStatusActionLabel";
+
+          // Select page 1 before merging.
+          await waitAndClick(
+            page,
+            `.thumbnail:has(${getThumbnailSelector(1)}) input`
+          );
+          await waitForTextToBe(page, labelSelector, `${FSI}1${PDI} selected`);
+
+          const handleMerged = await createPromise(page, resolve => {
+            window.PDFViewerApplication.eventBus._on(
+              "thumbnailsloaded",
+              resolve,
+              { once: true }
+            );
+          });
+
+          const picker = await page.$("#viewsManagerAddFilePicker");
+          await picker.uploadFile(
+            path.join(__dirname, "../pdfs/three_pages_with_number.pdf")
+          );
+          await awaitPromise(handleMerged);
+
+          // Original 3 pages + 3 merged pages = 6 pages total.
+          await page.waitForFunction(
+            () => parseInt(document.getElementById("pageNumber").max, 10) === 6
+          );
+
+          // Label must show exactly the 3 newly inserted pages — the
+          // pre-merge selection of page 1 must have been cleared.
+          await waitForTextToBe(page, labelSelector, `${FSI}3${PDI} selected`);
+
+          // Focus must move to the first newly inserted page (page 2).
+          await page.waitForFunction(
+            () => window.PDFViewerApplication.page === 2
+          );
+        })
+      );
+    });
   });
 });
diff --git a/web/pdf_thumbnail_viewer.js b/web/pdf_thumbnail_viewer.js
index dcd2e4128..1c005d69d 100644
--- a/web/pdf_thumbnail_viewer.js
+++ b/web/pdf_thumbnail_viewer.js
@@ -339,6 +339,11 @@ class PDFThumbnailViewer {
           this.eventBus._on(
             "thumbnailsloaded",
             () => {
+              // Clear any pre-merge selection: thumbnails are rebuilt fresh
+              // (all unchecked), so the old set would cause a label/visual
+              // mismatch.
+              this.#selectedPages = null;
+              this.#updateMenuEntries();
               this.#toggleBar("status");
               const newPagesCount = this.#pagesMapper.pagesNumber;
               const insertedPagesCount = newPagesCount - pagesCount;
@@ -351,6 +356,9 @@ class PDFThumbnailViewer {
                 this._thumbnails[i].checkbox.checked = true;
                 this.#selectPage(i + 1, true);
               }
+              if (insertedPagesCount) {
+                this.#updateCurrentPage(currentPageIndex + 2);
+              }
             },
             { once: true }
           );