diff --git a/apps/client/src/services/syntax_highlight.ts b/apps/client/src/services/syntax_highlight.ts
index bfe887b9d..cb2d4d873 100644
--- a/apps/client/src/services/syntax_highlight.ts
+++ b/apps/client/src/services/syntax_highlight.ts
@@ -97,7 +97,7 @@ export function loadHighlightingTheme(themeName: string) {
  */
 export function isSyntaxHighlightEnabled() {
     const theme = options.get("codeBlockTheme");
-    return theme && theme !== "none";
+    return !!theme && theme !== "none";
 }
 
 /**
diff --git a/apps/client/src/widgets/type_widgets/ckeditor/config.ts b/apps/client/src/widgets/type_widgets/ckeditor/config.ts
index 93eea459d..5a3262a1c 100644
--- a/apps/client/src/widgets/type_widgets/ckeditor/config.ts
+++ b/apps/client/src/widgets/type_widgets/ckeditor/config.ts
@@ -111,7 +111,7 @@ export function buildConfig(): EditorConfig {
             },
             mapLanguageName: getHighlightJsNameForMime,
             defaultMimeType: MIME_TYPE_AUTO,
-            enabled: isSyntaxHighlightEnabled
+            enabled: isSyntaxHighlightEnabled()
         },
         clipboard: {
             copy: copyText
diff --git a/packages/ckeditor5/src/augmentation.ts b/packages/ckeditor5/src/augmentation.ts
index da5e1c915..c1018db37 100644
--- a/packages/ckeditor5/src/augmentation.ts
+++ b/packages/ckeditor5/src/augmentation.ts
@@ -22,28 +22,3 @@ declare global {
         importMarkdownInline(): void;
     }
 }
-
-declare module "ckeditor5" {
-    interface Editor {
-        getSelectedHtml(): string;
-        removeSelection(): Promise<void>;
-    }
-
-    interface EditorConfig {
-        syntaxHighlighting?: {
-            loadHighlightJs: () => Promise<any>;
-            mapLanguageName(mimeType: string): string;
-            defaultMimeType: string;
-            enabled: boolean;
-        },
-        moveBlockUp?: {
-            keystroke: string[];
-        },
-        moveBlockDown?: {
-            keystroke: string[];
-        },
-        clipboard?: {
-            copy(text: string): void;
-        }
-    }
-}
diff --git a/packages/ckeditor5/src/index.ts b/packages/ckeditor5/src/index.ts
index 8dc0e3611..58e72ca6d 100644
--- a/packages/ckeditor5/src/index.ts
+++ b/packages/ckeditor5/src/index.ts
@@ -43,3 +43,28 @@ export class PopupEditor extends BalloonEditor {
         return POPUP_EDITOR_PLUGINS;
     }
 }
+
+declare module "ckeditor5" {
+    interface Editor {
+        getSelectedHtml(): string;
+        removeSelection(): Promise<void>;
+    }
+
+    interface EditorConfig {
+        syntaxHighlighting?: {
+            loadHighlightJs: () => Promise<any>;
+            mapLanguageName(mimeType: string): string;
+            defaultMimeType: string;
+            enabled: boolean;
+        },
+        moveBlockUp?: {
+            keystroke: string[];
+        },
+        moveBlockDown?: {
+            keystroke: string[];
+        },
+        clipboard?: {
+            copy(text: string): void;
+        }
+    }
+}