Set selection as dirty when unbinding from frame

saschanaz · moz-wptsync-bot · commit bbb3bb005f01 · 2025-10-17T09:45:06.000+01:00
Differential Revision: https://phabricator.services.mozilla.com/D268527 bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1993351 gecko-commit: a0e6fc95407993cca739629778fd25820f816a0a gecko-reviewers: masayuki
diff --git a/html/semantics/forms/the-textarea-element/selection-after-whitespace-change.html b/html/semantics/forms/the-textarea-element/selection-after-whitespace-change.html
@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<textarea id="t" style="white-space: nowrap">Hello</textarea>
+<script>
+promise_test(async () => {
+  t.focus();
+  if (navigator.userAgent.includes("Mac")) {
+    // Meta+ArrowLeft
+    await new test_driver.Actions()
+      .keyDown("\uE03D")
+      .keyDown("\uE058")
+      .keyUp("\uE058")
+      .keyUp("\uE03D")
+      .send();
+  } else {
+    // Home
+    await test_driver.send_keys(t, ["\uE011"]);
+  }
+  // And then Delete
+  await test_driver.send_keys(t, ["\uE017"]);
+  t.style.whiteSpace = "pre-line";
+  await new Promise(setTimeout);
+  assert_equals(t.selectionStart, 0, "selectionStart should remain 0");
+  assert_equals(t.selectionEnd, 0, "selectionEnd should remain 0");
+}, "Changing white-space should not change selection");
+</script>
