From d11d6d401bc92a3870ec1089d97235b01a6b27c3 Mon Sep 17 00:00:00 2001
From: Ghadeer Albattarni
 <165973963+GhadeerAlbattarni@users.noreply.github.com>
Date: Tue, 24 Feb 2026 08:53:05 -0500
Subject: [PATCH] fix: prevent viewer crash when opening DICOM Tag Browser from
 empty viewport  (#5827)

---
 extensions/default/src/commandsModule.ts |  4 +-
 tests/DicomTagBrowser.spec.ts            | 53 ++++++++++++++++++++++++
 tests/pages/DicomTagBrowserPageObject.ts |  9 ++--
 3 files changed, 62 insertions(+), 4 deletions(-)

diff --git a/extensions/default/src/commandsModule.ts b/extensions/default/src/commandsModule.ts
index b9569f37d..9f18269f5 100644
--- a/extensions/default/src/commandsModule.ts
+++ b/extensions/default/src/commandsModule.ts
@@ -656,7 +656,9 @@ const commandsModule = ({
       const displaySets = displaySetService.activeDisplaySets;
       const { UIModalService } = servicesManager.services;
 
-      const defaultDisplaySetInstanceUID = displaySetInstanceUID || displaySetInstanceUIDs[0];
+      const defaultDisplaySetInstanceUID =
+        displaySetInstanceUID || displaySetInstanceUIDs[0] || displaySets[0]?.displaySetInstanceUID;
+
       UIModalService.show({
         content: DicomTagBrowser,
         contentProps: {
diff --git a/tests/DicomTagBrowser.spec.ts b/tests/DicomTagBrowser.spec.ts
index f1cc09fde..49b5460e6 100644
--- a/tests/DicomTagBrowser.spec.ts
+++ b/tests/DicomTagBrowser.spec.ts
@@ -60,3 +60,56 @@ test('should display the long series name properly within the series select butt
     outerBoxLabel: 'trigger',
   });
 });
+
+test('should open DICOM Tag Browser from empty viewport and show default series', async ({
+  page,
+  mainToolbarPageObject,
+  viewportPageObject,
+  DOMOverlayPageObject,
+}) => {
+  const studyInstanceUID = '1.3.6.1.4.1.25403.345050719074.3824.20170125095258.1';
+  const mode = 'viewer';
+  await visitStudy(page, studyInstanceUID, mode, 2000);
+
+  // Switch to 3x3 layout
+  await mainToolbarPageObject.layoutSelection.click();
+  await page.getByTestId('Layout-2-2').click();
+
+  await viewportPageObject.getNth(6).pane.click();
+
+  await mainToolbarPageObject.moreTools.tagBrowser.click();
+
+  const dicomTagBrowser = DOMOverlayPageObject.dialog.dicomTagBrowser;
+  await dicomTagBrowser.waitVisible();
+
+  const seriesSelect = dicomTagBrowser.seriesSelect;
+  const optionText = await seriesSelect.getOptionText(0);
+
+  await expect(seriesSelect.value).toContainText(optionText);
+});
+
+test('should open DICOM Tag Browser with active viewport series when viewport has display set', async ({
+  page,
+  mainToolbarPageObject,
+  viewportPageObject,
+  DOMOverlayPageObject,
+}) => {
+  const studyInstanceUID = '1.3.6.1.4.1.25403.345050719074.3824.20170125095258.1';
+  const mode = 'viewer';
+  await visitStudy(page, studyInstanceUID, mode, 2000);
+
+  await mainToolbarPageObject.layoutSelection.click();
+  await page.getByTestId('Layout-2-2').click();
+
+  await viewportPageObject.getNth(2).pane.click();
+
+  await mainToolbarPageObject.moreTools.tagBrowser.click();
+
+  const dicomTagBrowser = DOMOverlayPageObject.dialog.dicomTagBrowser;
+  await dicomTagBrowser.waitVisible();
+
+  const seriesSelect = dicomTagBrowser.seriesSelect;
+  const optionText = await seriesSelect.getOptionText(2);
+
+  await expect(seriesSelect.value).toContainText(optionText);
+});
diff --git a/tests/pages/DicomTagBrowserPageObject.ts b/tests/pages/DicomTagBrowserPageObject.ts
index ff94ba0d1..24b0883c1 100644
--- a/tests/pages/DicomTagBrowserPageObject.ts
+++ b/tests/pages/DicomTagBrowserPageObject.ts
@@ -29,13 +29,16 @@ export class DicomTagBrowserPageObject {
         await trigger.click();
       },
 
-      async selectOption(index) {
+      async getOptionText(index) {
         await this.click();
         const optionText = await options.nth(index).innerText();
-        const selectedText = optionText.split('\n')[0].trim();
+        const trimmedOptionText = optionText.split('\n')[0].trim();
+        return trimmedOptionText;
+      },
 
+      async selectOption(index) {
+        const selectedText = await this.getOptionText(index);
         await options.nth(index).click();
-
         return selectedText;
       },
     };