Vim can't scroll in iTerm2

Question

My vim can't scroll in iTerm2 even set mouse=a has added in .vimrc file.

Within tmux, however, vim's scroll function works correctly.

What's wrong with my vim?

Answer 1

Recent versions of vim support the "SGR" protocol, you can add code bellow to your .vimrc:

set mouse=a
if has("mouse_sgr")
    set ttymouse=sgr
else
    set ttymouse=xterm2
end

Answer 2

I had the same issue, and Valery's answer did not work for me. What did work is checking the "Enable mouse reporting" box under Profiles > Terminal in the iTerm preferences.