Make the code folding icons always show in Visual Studio Code

To change the color of the gutter, you can add following to the user settings:

"workbench.colorCustomizations": {
    "editorGutter.background": "#abcdef"
}

And to show folding icons:

"editor.showFoldingControls": "always"

Note that this setting requires you to have at least 1.13.

you can make code folding icons appear persistently by addding : "editor.showFoldingControls": "always", but not in the "workbench.colorCustomizations", just put it outside and it will work. example:

"editor.showFoldingControls": "always",
"workbench.colorCustomizations": {
    "editor.renderIndentGuides": true,
    "scrollbarSlider.background": "#474552",
    "scrollbarSlider.hoverBackground": "#295377",
},

and since the [+][-] icons were replaced with [>][v], you can use this extension to regain this feature: Minimalist Product Icon Theme

I know this is an old thread, but FWIW:

File > Preferences > Settings

User > Text Editor > Editor: Show Folding Controls

Select "Always"

You cannot make code folding icons appear persistently. It is discussed here on project github page however it is not implemented yet.

If you want proper indentation your best bet is indentation guides (the vertical lines that run down to matching indents).

Indentation guides are not displayed by default.
To enable indent guides go to File --> Preferences --> Settings and then place following line in settings.json file,

"editor.renderIndentGuides": true