No, in the free version, you can only have one capability or role in the field. In the Pro version, you can actually enter a comma-separated list, and it will work as you would expect (though there are easier ways to set role permissions in the Pro version).
As to why adding Editor prevents Administrators from seeing the menu:
While the default WP roles look like they form a clear hierarchy (i.e. Administrator is "greater" than Editor and so on), that's not actually the case in general. For example, it would be entirely possible to create a custom role that has some capabilities that only Administrators have, but lacks some of the capabilities of an Editor.
Overall, there is no general and reliable way to determine if a given role is lesser on greater than another - except for the default roles, that is, where the relations could be hard-coded (and even that could fail if the user was to edit the default roles). So entering a role ID in the "required capability" field will restrict the menu to that specific role.