Garth,

Well, I read your post 20 times trying to understand what you mean, but I can't make head or tails of it.
1 - Where did/do you find the command Choose plan, because I definitely can't find it anywhere!

So, here are more questions:
2 - which version do you use: online, or installed?
3 - if installed: which SH3D version do you use: v2.6 or v3.0?
4 - what operating system do you use?
5 - can you share your file, so we can check if it is corrupted? (use www.mediafire.com to provide a link to it)
6 - which actions are you taking exactly trying to copy a furniture item?

- CTRL-C and CTRL-V don't work in the online version, but should work in the installed version, where you can also use Edit --> Copy and Edit --> Paste.

Hans