After Releasing ColorAnvil 1.3.4 with the GUI. 1.13 did not like it because of the use of a Material that was used for 1.12 but didn't exist in 1.13, so this version is a slight fix. the golden sword has been changed to a diamond sword so both versions will work.
I Apologize if anyone was using 1.13 with my plugin and could not access the help GUI.