Delete a Theme from the Legend to the Map Page Layout
From IMSMA Wiki
If you disable a theme, the theme is automatically deleted from the legend. However, you can delete a theme from the legend while keeping the theme enabled. To delete an enabled theme from the legend:
- From the Legend Themes pane, select the theme that you would like to delete.
- Click the button.
- The theme is deleted from the legend, but its symbol still displays on the map.