Sometimes copy and paste inside Vim using mouse over remote connection does not work as expected.
It is a rare situation, but it can happen to you at one time or another.
The solution is to use mouse option.
'mouse' string (default "", "a" for GUI, MS-DOS and Win32,
set to "a" in defaults.vim)
global
{not in Vi}
Enable the use of the mouse. Only works for certain terminals
(xterm, MS-DOS, Win32 win32-mouse, QNX pterm, *BSD console with
sysmouse and Linux console with gpm). For using the mouse in the
GUI, see gui-mouse.
The mouse can be enabled for different modes:
n Normal mode and Terminal modes
v Visual mode
i Insert mode
c Command-line mode
h all previous modes when editing a help file
a all previous modes
r for hit-enter and more-prompt prompt
Normally you would enable the mouse in all four modes with:
:set mouse=a
When the mouse is not enabled, the GUI will still use the mouse for
modeless selection. This doesn't move the text cursor.
See mouse-using. Also see 'clipboard'.
Note: When enabling the mouse in a terminal, copy/paste will use the
"* register if there is access to an X-server. The xterm handling of
the mouse buttons can still be used by keeping the shift key pressed.
Also see the 'clipboard' option.
Inspect mouse option.
:set mouse?
mouse=
Set mouse option to r or v.
:set mouse=r
Enjoy!