I am the developer of the mapping plugin mapsmarker.com and I am having troubles fixing an issue reported by my users using IE11:
please open the demo map at [[LINK href="https://demo.mapsmarker.com/wp-admin/admin.php?page=leafletmapsmarker_marker&id=16"]]https://demo.mapsmarker.com/wp-admin/admin.php?page=leafletmapsmarker_marker&id=16[[/LINK]] with IE11, try to change the icon (please take another one than the default blue pin which is shown first) and save the map clicking the button "update". With IE11 only the icons switches back to the default blue pin - other browsers work fine.
Please note that due to the dynamic editor switching feature (by the link "switch to advanced/simplified editor" right above the top of the editor), there are 2 divs available which contain the icons: one for the simplified editor and one for the advanced editor. The icons are selected via forms/radio buttons and are available twice with the same ID (needed for dynamic editor switching).
When updating an existing map, the $_POST['icon'] value is used to update the entry via a sql update (see [[LINK href="https://github.com/robertharm/Leaflet-Maps-Marker/blob/dev/leaflet-marker.php#L108"]]https://github.com/robertharm/Leaflet-Maps-Marker/blob/dev/leaflet-marker.php#L108[[/LINK]] for an example from the free version).
Only on IE11, not the selected value for the active icon is used, but the default one. Only IE11 seems to have problems with form icon elements being available twice with the same ID.
Any hints on how to solve this issue would really be appreciated!