That's just the right-click menu. Some laptop track pads have finger motions (or positions on the pad) that activate that menu.

If it's not a laptop (i.e. not a trackpad), it's possible your mouse is malfunctioning.

If you have another (regular not trackpad) mouse laying around you can use, see if using that gets rids of the issue.

Maybe it's a stuck key? Something that triggers a keyboard shortcut that makes that menu pop up?

Just one reason for the suggestion to try a different mouse.

The keyboard shortcut for right-click is shift-F10 ... pretty unlikely to do accidentally

That actually have a 'menu' key, along with a 'windows' key stuck in between the ctrl and alt buttons.

If that key went flakey, it might cause this too.

And one that would be ruled out if changing one's mouse rids one of the problem.

The mouse is my first guess as well.

But I'm an old indepent techie guy that does my own builds and repairs...and ran into a lot of weird stuff over the years that you wouldn't think would be responsible for certain problems.

Just giving the OP other a avenues to check, depending on what they have.

Sorry didnt answer before. Was away.
The finger motions sound like the answer, will have to digest, thanks will check more Settings and get back

I use ONE finger (the long, or "bad" one), such that the forefinger is always sort of hovering next to it over the touchpad, and I guess (NOW) that it sometimes touches down on the pad thereby turning things into the "TWO FINGER" gesture meaning the right-click menu (as I see now in the Settings).

I just got back to the machine, so just now unclicked the 2 finger deal and haven't done the time yet to see if it's been fixed, but it sounds like the answer.

Thanks, much!!!!!!!!!! You seem to hang out here, responsively!

But are your desktop and taskbar both black?

If so, I think your taskbar has been expanded upwards. To fix right click taskbar and unlock then wrangle it back to its proper height.

Otherwise, try using up and down arrows to scroll, making sure the window is active first.