Comment 4 for bug 167191

reopening: current versions of X11/Xquartz _do_ receive X events for horizontal scrolling with <Shift>+mouse wheel (verified with xev).

Other widgets inside Inkscape itself know about <Shift>+mouse wheel and scroll horizontally as expected (examples are the palette window just below the canvas, or the pane on the right side in the preferences dialog.

Interestingly using the trackpad to scroll horizontally as well as tilting the mouse wheel left/right (if available) does scroll the main canvas horizontally.

-> Possibly some (internally hard-coded) shortcut filtering grabs the 'Shift' event for the main window and in effect disables that X11 and/or the osx system receive the key press state when using the mouse wheel to scroll the canvas horizontally.

tested with on OS X 10.5.8 with XQuartz 2.4.0:
- Inkscape 0.47 r22583
- Inkscape 0.47+devel r9506 (local build)
- gtk-demo, installed gtk2 @2.20.1 (x11) using MacPorts