How to create a customized system tray icon?

[Jaydon]

Like the title says, a lot of my software shows up as white squares in the system tray because it’s third party software. How can I modify the white scheme to use a custom icon?

[alimirjamali]

It is not easy as many of those icons are dynamically generated and are not fixed png or svg files. Examples of dynamic icons are Wireless signal strength icon and Whonix’s Tor status widget.

But you can change the default filter Qubes applies on those icons. It is in Settings => Qubes Tools => Qubes Global Config => General Settings => Tray icon style.
login/logoff might be necessary after changes.

p.s.:
Also please see this post:

Where are system tray icons located?

It is necessary to understand that some of those icons might not be actual png or svg files but rather dynamically generated. Examples are WiFi signal strength icon and Tor connection status icon. There are easy workarounds to make them grayscale. Just change the label color of the VM which the tray icon app belongs to to gray. But since that trick won’t have any effect on Qubes Domain and Qubes Devices systray icons, here are their actual location for Qubes Domains: find /usr/share/icons/hicol…