diff --git a/shell/platform/common/text_input_model.cc b/shell/platform/common/text_input_model.cc
index a21fe1ff3effa..ea94830fcb9a4 100644
--- a/shell/platform/common/text_input_model.cc
+++ b/shell/platform/common/text_input_model.cc
@@ -79,8 +79,7 @@ void TextInputModel::UpdateComposingText(const std::u16string& text,
       composing_range_.collapsed() ? selection_ : composing_range_;
   text_.replace(rangeToDelete.start(), rangeToDelete.length(), text);
   composing_range_.set_end(composing_range_.start() + text.length());
-  selection_ = TextRange(selection.start() + composing_range_.start(),
-                         selection.extent() + composing_range_.start());
+  selection_ = TextRange(composing_range_.end());
 }
 
 void TextInputModel::UpdateComposingText(const std::u16string& text) {
diff --git a/shell/platform/windows/text_input_plugin.cc b/shell/platform/windows/text_input_plugin.cc
index a67eca476c7e0..8d3e545659983 100644
--- a/shell/platform/windows/text_input_plugin.cc
+++ b/shell/platform/windows/text_input_plugin.cc
@@ -197,6 +197,7 @@ void TextInputPlugin::ComposeChangeHook(const std::u16string& text,
   std::string text_before_change = active_model_->GetText();
   TextRange composing_before_change = active_model_->composing_range();
   active_model_->AddText(text);
+  cursor_pos += active_model_->composing_range().extent();
   active_model_->UpdateComposingText(text, TextRange(cursor_pos, cursor_pos));
   std::string text_after_change = active_model_->GetText();
   if (enable_delta_model) {