Scrolling on file is not fluid below ion-textarea with placeholder

I want display file user upload below ion textarea, but the scroll is not fluid.

When I remove placeholder the horizontal scroll is fluid.

When placeholder is displayed the scroll is not fluit.

When I write text, whatever the number of lines, placeholder disapear and scrolling is fluid.

How can I correct this problem

html code

<ion-footer *ngIf="kickedOut == 0">
  <ion-toolbar class="message_row">


      <ion-col size="1" class="col">
        <ion-icon class="trombonne" (click)="showSourceFile()" name="attach-outline"></ion-icon>

      <ion-col size="10">
        <ion-textarea autosize  scrollbar="true" rows="1" max-rows="10" type="text" placeholder="Tapez un message..." [(ngModel)]="userContent"></ion-textarea>

      <ion-col size="1" class="col">
        <!--Keyboard stay open when you send message -->
        <ion-icon class="send" name="send" (mousedown)="EnvoiCmt();$event.preventDefault()"
          [ngStyle]="{ 'color': (userContent != '' ||  fichiers.length != 0 ? 'var(--ion-color-primary)' : 'var(--ion-color-medium)')}">

    <ion-row class="FileContent">
      <ion-list *ngIf="fichiers.length !== 0" [ngClass]="{'margin-bottom':fichiers.length !== 1}" class="fileRow">
        <app-fichier (fichierEventEmitter)="removeFile($event)" *ngFor="let fichier of fichiers; let i = index"
          [indexOfFichier]="i" [image]="fichier.image" [filedoc]="fichier.fileDoc" [inPost]="false" >



 .message_row {
    background-color: #fff;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 2px;
  .col {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 35px;
     display: flex;
    justify-content: center;
    align-items: center;
    background-color: transparent;
    transform: rotate(135deg);
    position: fixed;

    width: 30px;

  ion-textarea {
    min-height: 30px;
    max-height: 50vh;
    overflow-y: auto;
    //resize: none;
    width: 100%;

    margin-left: 10px;
    margin-right: 10px;


.fileRow {
    height: auto;
    width: 100%;
    display: flex;
    flex-direction: row;
    align-items: top;
    overflow-x: scroll;
    overflow-y: hidden;
    white-space: nowrap;
    flex-wrap: nowrap;
    margin-top: 8px;