Text in Textarea is not scrolling with ng-repeat with ionic- angular js

When i using textarea below the ng-repeat in angular js - ionic . The text area is not working properly and some time lost it focus also. Please provide me solution for that this is my code :

                <div class="title">Comments</div>
                <ul class="comment_list">
                    <li ng-repeat="x in comments ">
                        <a><img no-image ng-src="{{profile_img_path.image_url_tiny+x.User.image}}" alt="" class="pro_img"></a>
                        <div class="pro_deatil" >
                            <h2> {{x.User.name}} </h2>
                            <p>{{x.CommentDish.comment}}</p>
                        </div>
                        <div class="pro_like" >

                        </div>
                        <div class="clearfix"></div>
                    </li>

                </ul>

                <div class="comment">
                    <textarea name="comment" rows="5" cols="10" ng-model="comment_data.comment" placeholder="Enter Comment" class="post_txt_area" overflow-scroll="true"></textarea>
                    <div> <a  ng-click="postComment()" class="event_btn">Comment</a> </div>
                </div>

Please help me if anyone has solution for this issue....