diff --git a/src/BookReader/Mode2UpLit.js b/src/BookReader/Mode2UpLit.js
index 4a1c81829..47844bd6c 100644
--- a/src/BookReader/Mode2UpLit.js
+++ b/src/BookReader/Mode2UpLit.js
@@ -676,6 +676,15 @@ export class Mode2UpLit extends LitElement {
 
     if (ev.which != 1) return;
 
+    // Don't flip the page if the user is completing a text-selection
+    // drag. The page-flip handler runs on `mouseup`, so releasing the
+    // mouse at the end of a selection would otherwise trigger
+    // `br.left()` / `br.right()` and clobber the selection. The text
+    // selection plugin's own mouseup handler stops propagation when the
+    // mouseup lands on a word, but not when it lands in blank space
+    // between words or on the page margin.
+    if (window.getSelection?.()?.toString().trim()) return;
+
     const $page = $(ev.target).closest('.BRpagecontainer');
     if (!$page.length) return;
     if ($page.data('side') == 'L') {