New type of group: columns

I found this issue looking for a way to show Field Groups in multiple columns, which is more simple than what is requested here, but I'll share my solution, in case anyone else ends up here, looking for the same.

I needed to show multiple Field Groups in two columns, to be used as Leaflet Pop Up source, and in my case it was pretty simple:

1. Create two new Field Groups of type "HTML Element", with class muni_col1 and muni_col2
2. Drag the existing Field Groups under these two new Field Groups, so that they were now the top level Field Groups
3. Add a little CSS

This resulted in a structure like this:

<div class="leaflet-popup-content">
  <div class="node__content">
    <div class="muni_col1">
      <div class="field-group">
        <h3>Column #1</h3>
      </div>
      <div class="field-group">
        <h3>Column #2</h3>
      </div>
    </div>
    <div class="muni_col2">
      <div class="field-group">
        <h3>Column #3</h3>
      </div>
      <div class="field-group">
        <h3>Column #4</h3>
      </div>
    </div>
  </div>
</div>

The CSS:

/* split up in two columns with Field group */
.leaflet-popup-content .node__content {
  display: flex;
}
.leaflet-popup-content .muni_col1,
.leaflet-popup-content .muni_col2 {
  width: 100%;
}

You can see it here, by clicking on an area of the map: https://arst.dk/kort