For example, a random thumbnail link on a Youtube channel will not appear, with just a white space in its place.
Or, at a local newspaper, some of the buttons to control display of the PDF edition, or parts of a banner ad, disappear in the same way.
Minimizing, then restoring, the tab remedies the problem, but of course it shouldn't be occurring in the first place.
I have absolutely followed all the steps to which you referred in your introductory posts, and this is strictly an Opera situation.
The monitor is a Dell 2009W analog, and I am quite aware that the company discontinued it, yet there are still plenty of them out there.