Yes 1.4 only handles visible items, the only exception on this is the step meta which can be inserted using ctrl+ins.
1.5 will allow for any meta ins/duplicate/copy/paste. If it's an unknown meta it will simply be handled as a comment.
I'm also planing to make the 1.5 version aware of LPub meta's so you can drag them from the part bin but this will probably not be in the first public alpha I'm planning.
To efficiently handle unknown meta's you could also setup templates though.
1.5 will allow for any meta ins/duplicate/copy/paste. If it's an unknown meta it will simply be handled as a comment.
I'm also planing to make the 1.5 version aware of LPub meta's so you can drag them from the part bin but this will probably not be in the first public alpha I'm planning.
To efficiently handle unknown meta's you could also setup templates though.