If you add the "errorbar" after _y_ou add the “legend”, the “legend” will automatically update to include the new “errorbar” handle. There are two ways around this.
You can add the “errorbar” before you add the “legend”:
% code for Line_1 and Line_2
errorbar(x, y, y_lower, y_upper, '.')
legend({'Line_1','Line_2'}) % The legend will only annotate the two labels you provided
Alternatively, if you need to add the “errorbar” after you add the “legend”, you can set the “errorbar” handle to be invisible. This will prevent the “legend” from updating with the new “errorbar” handle:
% code for Line_1 and Line_2
legend({'Line_1','Line_2'})
errorbar(x, y, y_lower, y_upper, '.', 'HandleVisibility','off') % The errorbar handle is not visible, preventing the legend from updating
