What you're describing here is an annoying touchpad feature called "Edge Swipes", which is enabled by default for Synaptics touchpads (and some other brands too).

Here's a link that will show you how to disable the Edge Swipes feature:

http://www.eightforums.com/tutorials/20992-touchpad-edge-swipes-enable-disable-windows-8-a.html

I'm pretty sure this will solve your problem.

My desktop is again Charms-free! 

Thanks for the tip!

Yes; exactly.  Easy fix, but for my trackpad (known on my Samsung as a "smart pad", I had to go to:

control panel--> mouse --> touchpad --> options

Not really obvious, but easy to poke around for once I had an objective.

Thanks!