There are two ways remove a layer in the Map Legend.
Delete Layer by Using Remove Layer Button in Map Legend
SELECT layer to remove
CLICK the remove layer icon in the Map Legend
The layer will disappear from the Map Legend, be sure to save changes to the map state in the Toolbar, to apply your changes.
OR
Delete Layer by Right-Clicking
SELECT layer to remove
RIGHT-CLICK on layer to remove
CHOOSE Remove Layer
Post your comment on this topic.