Need table scroll instead of body scroll when placed within CSS grid

Question

I have a table placed within a div. The table goes beyond the width of the div. And the div has overflow-x set to scroll. Below code works alright

body {
  margin: 0;
}

.table-section {
  width: 100%;
  overflow-x: scroll;
  padding: 10px;
  background-color: lightblue;
}

.table-section table {
  background-color: royalblue;
}

.table-section table th {
  min-width: 150px;
}

<div class="table-section">
    <table>
      <thead>
        <tr>
          <th>
            Col 1
          </th>
          <th>
            Col 2
          </th>
          <th>
            Col 3
          </th>
          <th>
            Col 4
          </th>
          <th>
            Col 5
          </th>
          <th>
            Col 6
          </th>
          <th>
            Col 7
          </th>
          <th>
            Col 8
          </th>
      </thead>
    </table>
  </div>

However, if I place the whole thing within a grid cell, the overflow-x does not seem to work. And the document body has the scroll. Code below:

body {
  margin: 0;
}

.grid {
  display: grid;
  grid-template-columns: 230px 1fr;
}

.table-section {
  grid-column: 2 / 3;
  width: 100%;
  overflow-x: scroll;
  padding: 10px;
  background-color: lightblue;
}

.table-section table {
  background-color: royalblue;
}

.table-section table th {
  min-width: 150px;
}

<div class="grid">
  <div class="table-section">
    <table>
      <thead>
        <tr>
          <th>
            Col 1
          </th>
          <th>
            Col 2
          </th>
          <th>
            Col 3
          </th>
          <th>
            Col 4
          </th>
          <th>
            Col 5
          </th>
          <th>
            Col 6
          </th>
          <th>
            Col 7
          </th>
          <th>
            Col 8
          </th>
      </thead>
    </table>
  </div>
</div>

Why is it not working within a grid-cell? And how do I fix it? Thanks.

Answer 1

I wouldn't normally mix tables with grids. Anyway, note that in Firefox 66 overflow works fine, while in Chrome it doesn't. Remove width: 100% from table-section and it works fine without it in both:

See demo below:

body {
  margin: 0;
}

.grid {
  display: grid;
  grid-template-columns: 230px 1fr;
}

.table-section {
  grid-column: 2 / 3;
  /*width: 100%;*/
  overflow-x: scroll;
  padding: 10px;
  background-color: lightblue;
}

.table-section table {
  background-color: royalblue;
}

.table-section table th {
  min-width: 150px;
}

<div class="grid">
  <div class="table-section">
    <table>
      <thead>
        <tr>
          <th>
            Col 1
          </th>
          <th>
            Col 2
          </th>
          <th>
            Col 3
          </th>
          <th>
            Col 4
          </th>
          <th>
            Col 5
          </th>
          <th>
            Col 6
          </th>
          <th>
            Col 7
          </th>
          <th>
            Col 8
          </th>
      </thead>
    </table>
  </div>
</div>

If your table is smaller than the grid cell - to fix, you can consider min-width: 100% and box-sizing: border-box to account for the padding in the width calculations:

body {
  margin: 0;
}

.grid {
  display: grid;
  grid-template-columns: 230px 1fr;
}

.table-section {
  grid-column: 2 / 3;
  min-width: 100%; /* changed */
  overflow-x: scroll;
  padding: 10px;
  background-color: lightblue;
  box-sizing: border-box; /* added */
}

.table-section table {
  background-color: royalblue;
}

.table-section table th {
  min-width: 150px;
}

<div class="grid">
  <div class="table-section">
    <table>
      <thead>
        <tr>
          <th>
            Col 1
          </th>
          <th>
            Col 2
          </th>
          <th>
            Col 3
          </th>
          <th>
            Col 4
          </th>
          <th>
            Col 5
          </th>
          <th>
            Col 6
          </th>
          <th>
            Col 7
          </th>
          <th>
            Col 8
          </th>
      </thead>
    </table>
  </div>
</div>