Comment 4 for bug 1860921

I came here looking for a fix to this for my Mint 19.3 (Ubuntu 18.04) install. So the problem may be older than 19.10.

The closest thing I've found to an explanation is here: https://askubuntu.com/questions/339593/missing-icons-for-headless-xfce-session-via-vnc But none of those fixes work.

One of the comments on that askubuntu post suggests a problem with xfsettingsd. Running xfsettingsd manually gives a few errors:

xfsettingsd-CRITICAL **: 12:49:29.776: RANDR extension is too old, version 1.1. Display settings won't be applied.
Xlib: extension "XInputExtension" missing on display ":1.0".

(xfsettingsd:20627): xfsettingsd-CRITICAL **: 12:49:29.780: XI is not present.

(xfsettingsd:20627): xfsettingsd-CRITICAL **: 12:49:29.780: Failed to initialize the Xkb extension.

(xfsettingsd:20627): xfsettingsd-CRITICAL **: 12:49:29.780: Failed to initialize the Accessibility extension.

I can confirm that xfwm4 is running. Restarting it gives a few errors:

(xfwm4:21159): xfwm4-WARNING **: 12:55:18.497: XSync extension too old (3.0).

(xfwm4:21159): xfwm4-WARNING **: 12:55:18.497: The display does not support the XRender extension.

(xfwm4:21159): xfwm4-WARNING **: 12:55:18.500: The display does not support the XComposite extension.

(xfwm4:21159): xfwm4-WARNING **: 12:55:18.500: The display does not support the XDamage extension.

(xfwm4:21159): xfwm4-WARNING **: 12:55:18.500: The display does not support the XFixes extension.

(xfwm4:21159): xfwm4-WARNING **: 12:55:18.501: The display does not support the XPresent extension.

(xfwm4:21159): xfwm4-WARNING **: 12:55:18.501: Compositing manager disabled.
Waiting for current window manager (Xfwm4) on screen :1.0 to exit: Done
xfwm4-Message: 12:55:18.822: Unsupported keyboard modifier '<Super>Tab'

(xfwm4:21159): xfwm4-WARNING **: 12:55:18.847: Cannot find visual format on screen 0