diff --git a/lib/core/editor/querya_code_editor.dart b/lib/core/editor/querya_code_editor.dart
index 6035aeb3..057b58e8 100644
--- a/lib/core/editor/querya_code_editor.dart
+++ b/lib/core/editor/querya_code_editor.dart
@@ -126,12 +126,12 @@ class _QueryaCodeEditorState extends State<QueryaCodeEditor> {
     _syncing = false;
   }
 
-  void _disposeHighlight() {
+  void _disposeHighlight([material.TextEditingController? externalToDetach]) {
     final highlight = _highlightController;
     if (highlight == null) return;
     highlight.removeListener(_onTextChanged);
     highlight.removeListener(_syncToExternal);
-    widget.controller?.removeListener(_syncFromExternal);
+    (externalToDetach ?? widget.controller)?.removeListener(_syncFromExternal);
     if (_ownsHighlightController) {
       highlight.dispose();
     }
@@ -230,7 +230,7 @@ class _QueryaCodeEditorState extends State<QueryaCodeEditor> {
     if (oldWidget.controller != widget.controller) {
       _highlightController?.removeListener(_onTextChanged);
       _plainController?.removeListener(_onTextChanged);
-      _disposeHighlight();
+      _disposeHighlight(oldWidget.controller);
       if (_plainController != null) {
         _plainController!.removeListener(_onTextChanged);
         if (_ownsPlainController) {
@@ -240,7 +240,6 @@ class _QueryaCodeEditorState extends State<QueryaCodeEditor> {
       }
       if (_useHighlighting) {
         _ensureHighlightController(context.queryaTheme);
-        _highlightController!.addListener(_onTextChanged);
       } else {
         _initPlainController(widget.controller);
         _plainController!.addListener(_onTextChanged);
diff --git a/test/core/editor/querya_code_editor_test.dart b/test/core/editor/querya_code_editor_test.dart
index 2eac736e..3d78133f 100644
--- a/test/core/editor/querya_code_editor_test.dart
+++ b/test/core/editor/querya_code_editor_test.dart
@@ -114,4 +114,58 @@ void main() {
     await tester.enterText(find.byType(material.EditableText), 'hello');
     expect(last, 'hello');
   });
+
+  testWidgets(
+      'updating controller does not register duplicate listener on highlight controller',
+      (tester) async {
+    final controller1 = material.TextEditingController(text: 'SELECT 1;');
+    final controller2 = material.TextEditingController(text: 'SELECT 2;');
+    int changeCount = 0;
+
+    await tester.pumpWidget(
+      queryaThemeTestShell(
+        child: material.SizedBox(
+          width: 400,
+          height: 200,
+          child: QueryaCodeEditor(
+            controller: controller1,
+            language: QueryaCodeLanguage.sql,
+            onChanged: (_) => changeCount++,
+          ),
+        ),
+      ),
+    );
+    await tester.pumpAndSettle();
+    await pumpSyntaxHighlightDebounce(tester);
+
+    // Update widget with new controller reference
+    await tester.pumpWidget(
+      queryaThemeTestShell(
+        child: material.SizedBox(
+          width: 400,
+          height: 200,
+          child: QueryaCodeEditor(
+            controller: controller2,
+            language: QueryaCodeLanguage.sql,
+            onChanged: (_) => changeCount++,
+          ),
+        ),
+      ),
+    );
+    await tester.pumpAndSettle();
+    await pumpSyntaxHighlightDebounce(tester);
+
+    changeCount = 0;
+    controller2.text = 'SELECT 3;';
+    await tester.pump();
+
+    // Verify onChanged fired exactly once (no duplicate listener registered)
+    expect(changeCount, 1);
+
+    // Verify old controller was detached
+    controller1.text = 'SELECT 999;';
+    await tester.pump();
+    expect(changeCount, 1);
+  });
 }
+