We were, at a stage, able to copy elements from one page and then, in another tab, paste them onto another page, weren´t we? Because it no longer works (the pasting part).
Hi Giri, how are you? 
If you have issues with copying and pasting elements using Ctrl-V / Ctrl-C , it may be an Editor issue. Please contact Wix Support team and provide them with as many details as possible so that they can try recreate it on their end.
Best,
Tal.