[themes] Allow to set a background color for settings / webview editors

[cyraid]

[Feature Request]
Set background color for generic windows.

[Suggestions]
window.bgColor, settings.bgColor, extensions.bgColor

[Reason]
I love my background color and all, but it only goes well with code.. Because I'm extremely used to a certain color set, but I'd rather separate code and information.

[bpasero]

@cyraid a precise explanation of what you want would certainly help. What is a generic window? What is settings background? What is extensions background color?

If you can draw over a screenshot to explain what you want, even better.

[cyraid]

Okay, thank you bpasero.

The empty group you were talking about works nicely when there are no windows:

That is the color I'd like to have all windows except for editing code.

Next, the settings window:

Notice how the settings have a blue background? It takes from my editor.background.

The extensions window:

Also takes from my editor.background, but since I use old school borland pascal colors, and have been programming since many ages ago, I'm used to those colors for code.. But not really for anything else (nor does it suit generic information windows).

It would be nice to customize the colors of those windows, and any other informational windows.

[bpasero]

@cyraid so you would like to have 2 new colors: a background color for settings editor and a background color for the rich-editor (not the text editor, but the one that can render rich text)?

[cyraid]

@bpasero yes please. Also fgColor of them too if possible.

[bpasero]

Passing along, not sure if some of this is possible already.

[leecookson]

I am interested in this...many foreground and meta object colors are allowed for settings, but otherwise, the background winds up matching my main edit theme colors. I'd prefer the settings page matches the workbench/list/treecolors.

Specifically, I have a light theme set for the "decorations" of the editor, and a dark theme for specifically the text editor. The settings page winds up with a dark background and oddly low-contrast foreground values, which I assume I'll wind up doing.

Also, if this Issue is resolved, I would like to see "Settings" fall under the "Workbench" category and not "Syntax": (#25986)