I've found that if I select the relevant objects from one layout, and then copy with ctrl+C, I can paste with ctrl+V into a different layout.
ONLY THEN it is possible to do the same on an event sheet: highlight , ctrl+C, and then ctrl+V into the other event sheet. Sometimes, you need to have atleast one event already in the sheet, or paste into a prexisting event and then pull them out. But from what I've found, the trick is copy and pasting the objects first.