-- Pressing mouse-2 while selecting or extending copies selection
-to the kill ring. Pressing mouse-1 or mouse-3 kills it.
-
-- Double-clicking mouse-3 also kills selection.
-
-- M-mouse-1, M-mouse-2 & M-mouse-3 work similarly to mouse-1, mouse-2
-& mouse-3, but operate on the X secondary selection rather than the
-primary selection and region."
+- mouse-2 while selecting or extending copies selection to the
+kill ring; mouse-1 or mouse-3 kills it."