Hello,
I'm trying to use rmb+sw-up/down as a mouse gesture (via systemsettings -> global shortcuts and gestures) across all browsers without resorting to browser plugins (chrome's suck more or less).

I got http://kde-apps.org/content/show.php/Mo ... ent=109576 but saw that there's no gesture for switching to the next/previous tab. I tried using the rmb+sw combination but it apparently isn't recognized (neither by the mouse gesture action, nor by the global shortcut thing).

Can something be done? Via xmodmap, perhaps, by adding a virtual key or something (I found the documentation too confusing to continue)?

Unfortunately the System Settings module doesn't support mouse buttons yet. For mouse gestures you hold down a button and "draw" something with your mouse, which is a bit different from what your description of what you want.

I wrote a guide some time ago about how to create mouse shortcuts with xbindkeys, but I'm not sure if it can do what you want - it would probably require that you make your right mouse button a modifier key, and then you wouldn't be able to use it normally.

If you want to use e.g. Shift + Scroll to switch to the previous/next tab you can map it to Ctrl + Tab and Ctrl + Shift + Tab using the guide above.