#1833 - Toolbar buttons are stuck to the main comment form (#1948)

* 1833 - Toolbar buttons are stuck to the main comment form

* Add readonly and JSDoc to CommentForm textareaId properties

Improve code quality based on review feedback: mark textareaId as
readonly since it should never change after construction, and add
JSDoc to static textareaCounter explaining its purpose.

---------

Co-authored-by: Dmitry Verkhoturov <paskal.07@gmail.com>

frontend/apps/remark42/app/components/comment-form/comment-form.spec.tsx

@@ -40,7 +40,7 @@ function setup(overrideProps: Partial<Props> = {}, overrideConfig: Partial<typeo
 describe('<CommentForm />', () => {
   afterEach(() => {
     // reset textarea id in order to have `textarea_1` for every test
-    CommentForm.textareaId = 0;
+    CommentForm.textareaCounter = 0;
     localStorage.clear();
   });
 

frontend/apps/remark42/app/components/comment-form/comment-form.tsx

@@ -58,7 +58,10 @@ const ImageMimeRegex = /image\//i;
 export class CommentForm extends Component<Props, State> {
   /** reference to textarea element */
   textareaRef = createRef<HTMLTextAreaElement>();
-  static textareaId = 0;
+  /** global counter for generating unique textarea IDs across all instances */
+  static textareaCounter = 0;
+  /** unique textarea ID for this instance */
+  readonly textareaId: string;
 
   state = {
     preview: null,
@@ -75,7 +78,8 @@ export class CommentForm extends Component<Props, State> {
 
     const savedComment = getPersistedComment(props.id);
     this.state.text = props.value ?? savedComment ?? '';
-    CommentForm.textareaId += 1;
+    CommentForm.textareaCounter += 1;
+    this.textareaId = `textarea_${CommentForm.textareaCounter}`;
   }
 
   componentWillReceiveProps(nextProps: Props) {
@@ -416,7 +420,6 @@ export class CommentForm extends Component<Props, State> {
       edit: <FormattedMessage id="commentForm.save" defaultMessage="Save" />,
       reply: <FormattedMessage id="commentForm.reply" defaultMessage="Reply" />,
     };
-    const textareaId = `textarea_${CommentForm.textareaId}`;
     const label = buttonText || Labels[mode || 'main'];
     const placeholderMessage = intl.formatMessage(messages.placeholder);
     const isSimpleView = StaticStore.config.simple_view;
@@ -443,14 +446,14 @@ export class CommentForm extends Component<Props, State> {
               intl={intl}
               allowUpload={Boolean(uploadImage)}
               uploadImages={this.uploadImages}
-              textareaId={textareaId}
+              textareaId={this.textareaId}
             />
           </div>
         )}
         <div className="comment-form__field-wrapper">
           <TextExpander>
             <TextareaAutosize
-              id={textareaId}
+              id={this.textareaId}
               ref={this.textareaRef}
               onPaste={this.onPaste}
               className="comment-form__field"