Firefox & MySQL admin have black line borders

Firefox & MySQL admin have black line borders. The tab, address input box, the search box, the scroll bars, and the dropdown menu area have this black line border. MySQL’s admin utility displays the same.

Can’t figure out where to change it.

Also other thread is about Desktop-Settings utility crashes. Should I just do a restore of user install defaults? How would I do that and save some of my desktop custom program icons?

That looks like a GTK issue.
I assume you’re using KDE. Try changing the GTK theme in System Settings > Appearance > GTK styles and Fonts > Use style: …

It will affect not only Firefox and MySQL admin but all other GTK based applications that you might have installed (Kde and Kde apps are not based on GTK)

As stated in other posts: AFAICS this is related to videocard. Please let us know brand and model.

First we have to see that you have a flawless desktop. Next thing will be custom program icons. If you work on one thing at the time and errors appear, we will at least know what caused them. c.q. where the cause is.