How to: Make Logitech Mid/Back/Forward buttons work in Opus

By default Logitech's SetPoint drivers assign the Middle, Back and Forward mouse buttons to non-standard functions which don't work in Opus and a number of other programs.

To make the Middle mouse button work in Opus -- so that you can use all three actions of Three-Buttons and also toggle-select files with just one hand -- edit the middle mouse button in SetPoint and assign it to Middle Button.

To make the Back and Forward buttons work in Opus (and Firefox, etc.), edit the Back and Forward buttons and assign each of them to Other -> Generic Button.

See Also: Another suggestion can be found here: Logitech middle click