Screen Color

I choose:
SETTINGS - PERSONALIZATION - BACKGROUND - SOLID COLOR (blue)
All looks windowswonderful . . .
EXIT

Open my wallpaper program (Webshots) and choose a portrait-oriented photo which does not fill the screen width.
- In Windows 7, whenever the wallpaper photo did not fill the screen (as a portrait-oriented pix usually would not), the remainder of the screen would remain the screen color chosen (blue).
- In "new, improved by MS programmers in the guaranteed employment department" Windows 10, however, when wallpaper presents a portrait-oriented pix, the background color (blue) disappears and is replaced by black.

Uh-huh . . .
Whose idea was this "improvement"! . . . and how can it be rectified? The screen color should, one would normally expect, remain whichever color is designated in SETTINGS -- regardless of whatever the screensaver photo or graphic superimposes places over it.

Anyone know a solution to offer?
Many thanks; appreciated.