When placing new map features, turn visibility on for all layer categories (for just the current layer).
Display the following transient message:
Message: Visibility is being turned on for all categories this layer because you are adding new items to the layer.
If the user edits the data fields for an item and the newly entered data will make the marker invisible, on save, display the following transient message:
Message:
The marker is not visible on the map because the visibility setting is OFF for layer "layer name", category "category name".
Example:
The marker is not visible on the map because the visibility setting is OFF for layer "Flowers", category "Perennial".
Message: Visibility is being turned on for all categories this layer because you are adding new items to the layer.
Message:
The marker is not visible on the map because the visibility setting is OFF for layer "layer name", category "category name".
Example: The marker is not visible on the map because the visibility setting is OFF for layer "Flowers", category "Perennial".