Two command names (new and old) cause the command division.

For some predefined commands, has a new name and old name. It tells the user to use the new one as preferred. If choosing the new command name to extend, will not works, that because of old names in the internal.

The reason is: In commands/index.js, the added or extended commands are the newly created views (extends from CommandAbstract).

Here is my code snippet, it not works if the defaultCommand option value is select-comp

const Command = editor.Commands.get('core:component-select')
editor.Commands.extend('core:component-select', {
  // Overwrite this private method to make the toolbar conditionally display.
  updateToolbar(mod) {
    ...
    Command.updateToolbar.call(this, mod)
  }
})