diff --git a/src/calibre/gui2/tweak_book/editor/text.py b/src/calibre/gui2/tweak_book/editor/text.py
index c32a76b632..c365bf7b40 100644
--- a/src/calibre/gui2/tweak_book/editor/text.py
+++ b/src/calibre/gui2/tweak_book/editor/text.py
@@ -503,20 +503,20 @@ class TextEdit(PlainTextEdit):
         if wrap and not complete:
             pos = QTextCursor.MoveOperation.End if reverse else QTextCursor.MoveOperation.Start
         c.movePosition(pos, QTextCursor.MoveMode.KeepAnchor)
-        raw = str(c.selectedText()).replace(PARAGRAPH_SEPARATOR, '\n').rstrip('\0')
         if hasattr(self.smarts, 'find_text'):
             self.highlighter.join()
             found, start, end = self.smarts.find_text(pat, c, reverse)
             if not found:
                 return False
         else:
+            raw = str(c.selectedText()).replace(PARAGRAPH_SEPARATOR, '\n').rstrip('\0')
             m = pat.search(raw)
             if m is None:
                 return False
             start, end = m.span()
             if start == end:
                 return False
-        end = start + utf16_length(raw[start:end])
+            end = start + utf16_length(raw[start:end])
         if reverse:
             start, end = end, start
         c.clearSelection()
diff --git a/src/calibre/gui2/tweak_book/text_search.py b/src/calibre/gui2/tweak_book/text_search.py
index d67c712dc8..aab65326a1 100644
--- a/src/calibre/gui2/tweak_book/text_search.py
+++ b/src/calibre/gui2/tweak_book/text_search.py
@@ -17,6 +17,7 @@ from calibre.gui2.tweak_book.search import (
 from calibre.gui2.widgets import BusyCursor
 from calibre.gui2.widgets2 import HistoryComboBox
 from calibre.startup import connect_lambda
+from calibre.utils.icu import utf16_length
 from polyglot.builtins import error_message, iteritems
 
 # UI {{{
@@ -219,7 +220,7 @@ def find_text_in_chunks(pat, chunks):
                 start_pos = chunk_start + (start - offset)
         if start_pos is not None:
             if contains(clen, after-1):
-                end_pos = chunk_start + (after - offset)
+                end_pos = chunk_start + utf16_length(chunk[:after-offset])
                 return start_pos, end_pos
         offset += clen
         if offset > after: