Annoying usermode contrast pop up box

While on my pc, a box occasionally pops up that blocks the screen.
It says: USER MODE CONTRAST. The box is blue with grey symbols all around
the inside edge.
On the top left corner, the symbol is RED while all others are greyed out.
At mid center left it reads H:37:8 and mid right center 9300.

It remains for only a few seconds at a time, but continually pops up all the
while I am online. Please help me with this annoying problem. I cannot find
any help in the knowledge base.