1. Select File > Preferences > Graphs.
2. To either delete a color theme, select either the Continuous or Categorical Color Theme.
The relevant Color Themes window appears.
3. Click the Custom Color Theme disclosure icon to show the Custom Color Theme panel.
4. From the appropriate pane, select the custom color to delete.
Note: You can delete only custom color themes.
5. Click Delete.
6. Click OK to save your changes and close the Color Themes window.