Logitech Life Mouse Shortcuts

My new vertical mouse just arrived and I want to map the side buttons (back/forward aka button 4 and 5). I did this on my previous mouse and it worked fine until the mouse buttons broke.

Blender detects the button press when i setup a keymap command but it simply will not work in the viewport.

I’m setting the button 4 to view3d.move. Saves me pressing shift. I can assign the button to a test command and it works but not for panning the viewport, although my previous mouse did.

Any idea?

for future reference - the horizontal scroll setting in logi options was preventing button 4 from being used!