Ah.. nevermind... PEBKAC..

I have one of these keyboards

https://compass-ssl.xboxlive.com/assets/62/8d/628d39fb-0944-4cc1-9260-60ba6fcffd27.jpg?n=SED_STop_FY16New.jpg

And the little "fn" switch in the upper right was accidentally betwixt
the two positions. No idea how that relates to the mouse, but sliding it
all the way to the right seems to have fixed things.

Apologies for the static.

On 08/11/2016 10:07 AM, dev wrote:
> Hello,
> I have a logitiech M570 wireless mouse hooked up to my Devuan desktop
> running LXDE. For the past week or so clicking the middle button
> (scroll wheel + button) sometimes pastes in two copies of the text,
> sometimes one copy, and sometimes nothing at all.
>
> I installed some updates earlier this week; don't remember what they
> were. Maybe something in there is messing with USB mouse?
>
> I've tried plugging the USB receiver into different ports as well as
> rebooting, and tried a new battery. Still the same.
>
> Is there some other way to fiddle with mouse settings other than what's
> under "Bird Menu" > preferences > keyboard and mouse?