Color configuration issue on Plasma

[dep]

Greetings . . .

I've installed and configured Ubuntu-18.04 with the Plasma desktop on a GPD Pocket computer, and the combination is remarkably nice and very useful.

In the course of configuring it I've been able to set colors, typefaces and font sizes, and so on almost entirely to my liking. The "almost" is because no matter what I do, I can't change the color of the windows' titlebar. I've told it to be white text on a black background (System Settings > Colors > Breeze High Contrast > Edit Scheme > Active Titlebar, then saved under a new name and chosen as the scheme to use). The other changes I have made seem to have been applied, but the window titlebar remains a kind of sky blue.

The window manager is, according to wmctrl, kwin. Is there a kwin configuration file I need to edit to make my titlebars nice and black? If not, what else might I try? I did a fairly long though probably not comprehensive search and found a few things that seemed close to but not entirely on point, and others that advised doing what I described above.

btw -- Plasma runs really, really well on the GPD Pocket -- better than I'd expected (though my last experiment was with the Gemini device, on which things are not as rosy).

Thanks in advance.

​dep

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