diff --git a/lib/core/editor/querya_code_editor.dart b/lib/core/editor/querya_code_editor.dart
index 0d0741e6..d696fdd9 100644
--- a/lib/core/editor/querya_code_editor.dart
+++ b/lib/core/editor/querya_code_editor.dart
@@ -63,6 +63,7 @@ class _QueryaCodeEditorState extends State<QueryaCodeEditor> {
   material.TextEditingController? _internalController;
   QueryaEditorTheme? _lastEditorTheme;
   int _lastTokenColorsHash = 0;
+  String? _lastText;
 
   material.TextEditingController get _effectiveController =>
       widget.controller ?? _internalController!;
@@ -76,11 +77,24 @@ class _QueryaCodeEditorState extends State<QueryaCodeEditor> {
 
   void _initControllerIfNeeded() {
     if (widget.controller == null) {
-      _internalController = material.TextEditingController();
+      _internalController = _createInternalController();
     }
   }
 
+  material.TextEditingController _createInternalController({
+    String? text,
+  }) {
+    if (!widget.enableHighlighting) {
+      return material.TextEditingController(text: text);
+    }
+    return SyntaxHighlightService.createHighlightController(
+      language: widget.language,
+      text: text,
+    );
+  }
+
   void _attachListener() {
+    _lastText = _effectiveController.text;
     _effectiveController.addListener(_onTextChanged);
   }
 
@@ -89,7 +103,10 @@ class _QueryaCodeEditorState extends State<QueryaCodeEditor> {
   }
 
   void _onTextChanged() {
-    widget.onChanged?.call(_effectiveController.text);
+    final currentText = _effectiveController.text;
+    if (currentText == _lastText) return;
+    _lastText = currentText;
+    widget.onChanged?.call(currentText);
   }
 
   void _syncThemeIfNeeded(
@@ -139,13 +156,18 @@ class _QueryaCodeEditorState extends State<QueryaCodeEditor> {
   @override
   void didUpdateWidget(QueryaCodeEditor oldWidget) {
     super.didUpdateWidget(oldWidget);
-    if (oldWidget.controller != widget.controller) {
+    final controllerChanged = oldWidget.controller != widget.controller;
+    final languageChanged = oldWidget.language != widget.language;
+    final highlightingChanged =
+        oldWidget.enableHighlighting != widget.enableHighlighting;
+
+    if (controllerChanged) {
       _detachListener(oldWidget.controller ?? _internalController);
       if (oldWidget.controller == null && widget.controller != null) {
         _internalController?.dispose();
         _internalController = null;
       } else if (widget.controller == null && _internalController == null) {
-        _internalController = material.TextEditingController();
+        _internalController = _createInternalController();
       }
       _lastEditorTheme = null;
       _lastTokenColorsHash = 0;
@@ -154,6 +176,23 @@ class _QueryaCodeEditorState extends State<QueryaCodeEditor> {
         context.queryaTheme,
         transitioning: QueryaThemeScope.isTransitioning(context),
       );
+    } else if (widget.controller == null &&
+        (languageChanged || highlightingChanged)) {
+      final oldController = _internalController!;
+      final currentText = oldController.text;
+      final currentSelection = oldController.selection;
+      _detachListener(oldController);
+      oldController.dispose();
+      _internalController = _createInternalController(
+        text: currentText,
+      )..selection = currentSelection;
+      _lastEditorTheme = null;
+      _lastTokenColorsHash = 0;
+      _attachListener();
+      _syncThemeIfNeeded(
+        context.queryaTheme,
+        transitioning: QueryaThemeScope.isTransitioning(context),
+      );
     }
   }
 
@@ -209,7 +248,6 @@ class _QueryaCodeEditorState extends State<QueryaCodeEditor> {
           contentPadding:
               widget.contentPadding ?? const material.EdgeInsets.all(12),
         ),
-        onChanged: widget.onChanged,
       );
     }
 
@@ -222,7 +260,6 @@ class _QueryaCodeEditorState extends State<QueryaCodeEditor> {
       expands: widget.expands,
       style: style,
       placeholder: placeholder,
-      onChanged: widget.onChanged,
     );
   }
 }
diff --git a/test/core/editor/querya_code_editor_test.dart b/test/core/editor/querya_code_editor_test.dart
index 5102cd5f..35000d81 100644
--- a/test/core/editor/querya_code_editor_test.dart
+++ b/test/core/editor/querya_code_editor_test.dart
@@ -2,6 +2,7 @@ import 'package:flutter/material.dart' as material;
 import 'package:flutter_test/flutter_test.dart';
 import 'package:querya_desktop/core/editor/querya_code_editor.dart';
 import 'package:querya_desktop/core/editor/querya_code_language.dart';
+import 'package:querya_desktop/core/editor/querya_highlight_controller.dart';
 import 'package:querya_desktop/core/editor/syntax_highlight_service.dart';
 import 'package:querya_desktop/core/theme/querya_theme.dart';
 import 'package:shadcn_flutter/shadcn_flutter.dart';
@@ -170,5 +171,145 @@ void main() {
     await tester.pump();
     expect(changeCount, 1);
   });
+
+  testWidgets('onChanged fires exactly once per text edit when typing',
+      (tester) async {
+    int count = 0;
+    await tester.pumpWidget(
+      queryaThemeTestShell(
+        child: material.SizedBox(
+          width: 400,
+          height: 200,
+          child: QueryaCodeEditor(
+            language: QueryaCodeLanguage.plain,
+            onChanged: (_) => count++,
+          ),
+        ),
+      ),
+    );
+    await tester.pumpAndSettle();
+    await tester.enterText(find.byType(material.EditableText), 'abc');
+    expect(count, 1);
+  });
+
+  testWidgets('cursor movement and selection changes do not trigger onChanged',
+      (tester) async {
+    int count = 0;
+    final controller = material.TextEditingController(text: 'initial text');
+    await tester.pumpWidget(
+      queryaThemeTestShell(
+        child: material.SizedBox(
+          width: 400,
+          height: 200,
+          child: QueryaCodeEditor(
+            controller: controller,
+            language: QueryaCodeLanguage.plain,
+            onChanged: (_) => count++,
+          ),
+        ),
+      ),
+    );
+    await tester.pumpAndSettle();
+
+    // Change selection without changing text
+    controller.selection = const material.TextSelection(
+      baseOffset: 0,
+      extentOffset: 5,
+    );
+    await tester.pump();
+
+    expect(count, 0);
+
+    // Tap the field to move cursor
+    await tester.tap(find.byType(material.EditableText));
+    await tester.pump();
+
+    expect(count, 0);
+  });
+
+  testWidgets(
+      'QueryaCodeEditor creates highlight controller by default for SQL',
+      (tester) async {
+    await tester.pumpWidget(
+      queryaThemeTestShell(
+        child: const material.SizedBox(
+          width: 400,
+          height: 200,
+          child: QueryaCodeEditor(
+            language: QueryaCodeLanguage.sql,
+            enableHighlighting: true,
+          ),
+        ),
+      ),
+    );
+    await tester.pumpAndSettle();
+
+    final editable = tester.widget<material.EditableText>(
+      find.byType(material.EditableText),
+    );
+    expect(editable.controller, isA<QueryaHighlightController>());
+  });
+
+  testWidgets(
+      'QueryaCodeEditor creates plain controller when enableHighlighting is false',
+      (tester) async {
+    await tester.pumpWidget(
+      queryaThemeTestShell(
+        child: const material.SizedBox(
+          width: 400,
+          height: 200,
+          child: QueryaCodeEditor(
+            language: QueryaCodeLanguage.sql,
+            enableHighlighting: false,
+          ),
+        ),
+      ),
+    );
+    await tester.pumpAndSettle();
+
+    final editable = tester.widget<material.EditableText>(
+      find.byType(material.EditableText),
+    );
+    expect(editable.controller, isNot(isA<QueryaHighlightController>()));
+  });
+
+  testWidgets(
+      'updating language updates internal controller and preserves text',
+      (tester) async {
+    await tester.pumpWidget(
+      queryaThemeTestShell(
+        child: const material.SizedBox(
+          width: 400,
+          height: 200,
+          child: QueryaCodeEditor(
+            language: QueryaCodeLanguage.plain,
+          ),
+        ),
+      ),
+    );
+    await tester.pumpAndSettle();
+    await tester.enterText(find.byType(material.EditableText), 'SELECT 1;');
+    await tester.pump();
+
+    // Rebuild with SQL language
+    await tester.pumpWidget(
+      queryaThemeTestShell(
+        child: const material.SizedBox(
+          width: 400,
+          height: 200,
+          child: QueryaCodeEditor(
+            language: QueryaCodeLanguage.sql,
+          ),
+        ),
+      ),
+    );
+    await tester.pumpAndSettle();
+
+    final editable = tester.widget<material.EditableText>(
+      find.byType(material.EditableText),
+    );
+    expect(editable.controller, isA<QueryaHighlightController>());
+    expect(editable.controller.text, 'SELECT 1;');
+  });
 }