Bug#799299: scrollbind: Mouse-scrolling works in right window but not in left window

[Daniel Shahaf]

Package: vim-gtk
Version: 2:7.4.826-1
Severity: normal

Dear Maintainer,

Using the mousewheel on 'scrollbind' windows works if the mouse pointer
is over one of the windows, but not if it is over the other.

To reproduce, start gvim as follows:

% cat > script.vim
:a
lorem
ipsum
dolor
sit
amet
..
:vsplit
:windo set scrollbind
% gvim -N -u NONE -S script.vim

At that point, using the mousewheel to scroll the windows behaves as
follows: if the mouse pointer is over the left window then the left
window is scrolled; if the mouse pointer is over the right-hand-side
window, both windows get scrolled.  I expected it to scroll both windows
regardless of which window the mouse pointer is over.

The behaviour is similar (but with the roles of left and right switched)
if the script is changed to run 'set scrollbind | vsplit | set scrollbind'
instead.

Cheers

Daniel


-- Package-specific info:

--- real paths of main Vim binaries ---
/usr/bin/vi is /usr/bin/vim.gtk
/usr/bin/vim is /usr/bin/vim.gtk
/usr/bin/gvim is /usr/bin/vim.gtk

-- System Information:
Debian Release: 8.2
  APT prefers stable
  APT policy: (500, 'stable'), (250, 'testing'), (200, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 3.16.0-4-amd64 (SMP w/1 CPU core)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages vim-gtk depends on:
ii  libacl1             2.2.52-2
ii  libc6               2.19-18+deb8u1
ii  libgdk-pixbuf2.0-0  2.31.1-2+deb8u2
ii  libglib2.0-0        2.42.1-1
ii  libgpm2             1.20.4-6.1+b2
ii  libgtk2.0-0         2.24.25-3
ii  libice6             2:1.0.9-1+b1
ii  liblua5.2-0         5.2.3-1.1
ii  libpango-1.0-0      1.36.8-3
ii  libperl5.20         5.20.2-3+deb8u1
ii  libpython2.7        2.7.9-2
ii  libruby2.1          2.1.5-2+deb8u2
ii  libselinux1         2.3-2
ii  libsm6              2:1.2.2-1+b1
ii  libtcl8.6           8.6.2+dfsg-2
ii  libtinfo5           5.9+20140913-1+b1
ii  libx11-6            2:1.6.2-3
ii  libxt6              1:1.1.4-1+b1
ii  vim-common          2:7.4.826-1
ii  vim-gui-common      2:7.4.826-1
ii  vim-runtime         2:7.4.826-1

vim-gtk recommends no packages.

Versions of packages vim-gtk suggests:
pn  cscope            <none>
ii  fonts-dejavu      2.34-1
ii  gnome-icon-theme  3.12.0-1
pn  vim-doc           <none>

-- no debconf information