This area was covered in a very old topic that's probably not watched anymore, so I'm raising it as a new query. The topic there uses css, but I'm not experienced with using css, but I do use ESRI assistant, so I was wondering if this can be done here too, and if so using what code where. I've tried adding various bits with 'height' etc in various places, but it makes no difference.
An additional, but hopefully related point. I changed the theme background to white (Hex ffffff), but this has meant that the widgets in the banner, being white on grey by default, have all vanished 🤔. Is there a way to set their colour, or do I need to save the icon and invert it?
I added the banner above the WAB when I had a total control over its display (see link). It is not easy to change the WAB banner beyond of what ESRI template config, since it involves changing the css code in the ESRI core files.