I cannot change the view to small icons, the choice is greyed out.
The mouse settings when I select mouse after Control Panel do not include an "Activities" tab.
However I found the double click speed and tried slowing the double click speed for both the built in touch pad and the external USB mouse.
Will let you know....
Nope.... These adjustments didn't help.
I will try the option for completely disabling the touch pad when the external mouse is connected next and let you know.