Installing the issue fork 3390605 did not solve the problem for me. The uploaded banner image disappeared again after about one day.
Thanks for your reply.
As the extension otherwise works fine, my workaround for now is to visit the site https://emojipedia.org, search for and select an emoji there, and copy paste it into the map marker field.
Have you been able to find a solution to get the icon picker working?
I may have a similar problem.
When adding a field for the map marker and try to use the "pick emoji" button, the site reloads, but I cannot select any emojis. Similar behavior happens when I try to select an emoji when creating/editing a content.
When clicking on the "pick emoji" button, the site reloads, but I cannot select anything.
However, when adding a character as default map marker it is shown on the map. So the map marker seems to work, only I cannot pick any emojis.
I don't see any errors in the drupal log or in the browser console.
Thanks for setting up the branch, this way I was able to upgrade.
Only one error: In the file drupal8_zymphonies_theme.theme, in Line 264 there should be a different bracket:
"]" instead of ")"
Otherwise the theme doesn't work.