I've encountered trouble with copy/paste function! I don't know why ,but it's working very rare! I do like follow: I select notes (with ctrl+ mouse) , press CTRL+ C (or "copy" from menu "edit") then I go to different stave , mark few bars(ctrl+ mouse) and press CTRL+V (or "paste" from "edit") and I don't see any copied notes.

I reopened Composer and it helped but for while only. Is anyone who has similar trouble ???