Vim inside Screen causes trailing spaces in clipboard

After a recent upgrade to Ubuntu 14.04 (Screen 4.01.00devel), I now 
have this behavior:

*** When I select a block of Vim text with no trailing spaces, I get 
trailing spaces in the pasted result. ****

This happens only when Vim is inside screen.

Here's a screenshot of the paste result using Vim to show the spaces 
and EOL.
https://db.tt/N7KkkF35

I can confirm with xclipboard that the spaces are there (i.e. they're 
not a result of pasting).

Also:

- It happens with no .screenrc present.

- It happens with 4.2.1 as well.

- This didn't happen with whatever screen shipped with Ubuntu 12.10.

- $SCREEN is set to 'screen'.

Any ideas?  Happy to help debug.