Why does my position:absolute element still mange to take space?

I’m trying to re-create a sort of a dropdown menu with multiple choices when clicked. However, the div i want to appear in position absolute still fill the space by making the div scrollable.

The clickable side is correctly implemented in Js by changing .select_cart_drop display to flex.

The goal would be to stack the drop div on the preview div in the wrapper of both of them.

Here is the code :

.select_cart {
  position: relative;
  width: 70%;
  border: 1px solid lightgray;
}

.select_cart_drop {
  position: absolute;
  */display: none;/*
  flex-direction: column;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1;
}

<div class="select_cart">
  <div class="cart_checkbox_label">
    <div class="select_cart_container_quantité">Quantité :</div>
  </div>
  <div class="select_cart_drop">
    <div>0 (supprimer)</div>
    <div>1</div>
    <div>2</div>
    <div>3</div>
    <div>4</div>
    <div>5</div>
    <div>6</div>
    <div>7</div>
    <div>8</div>
    <div>9</div>
    <div>10 +</div>
  </div>
</div>