Well.. If the alias is in "myaliases.alias", it should NOT be read-only and you should be able to delete the entry by right-clicking it and selecting "delete".
If you can't, please check farr's directory -> AliasGroups -> Installed, and check if myalias.alias is there. If it is, please move it to AliasGroups -> MyCustom.
All the aliases under the "installed" directory are read-only, maybe that one ended up there by error