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I have three cheap mouses which has two extra mouse buttons for going forward and backward. However, two of them have the xbutton1 (the one which performs backward) closer to me but one have it farther from me.
Which is the standard? I tried some googling but nothing useful turned out.
Just FYI, these buttons are on the side, lies left to the left mouse button, and can easily be pressed by the thumb. The one closer to me can be pressed easier than the one farther from me.