Hi,
As you can see from the screenshot, there is a gap indicated by the arrow where my NextCloud icon lives. Unfortunately, it can’t be seen and adjusting the mask in Panel Colorizer doesn’t do anything. If I switch to the default Breeze theme, it can be seen but using the Black Glass theme it can’t. A suggestion I found on this forum was to put the nextcloud.svg file into the icons directory of the theme, i.e in
/home/peter/.local/share/plasma/desktoptheme/blackglass/icons/
I did that and it’s still a no go. So, where is this tray icon layout being sourced from? I’m pretty handy with Inkscape so if it needs a newer/better icon or a different coloured one, that’s a cinch to do too. I just need to know where to put it. 
Also, the adjust brightness icon seems to be missing under the icon set I use - DarK-svg. Again, I can fix this and create one for it if I know what KDE actually names this icon. Right clicking it doesn’t actually tell me. is it the brightness-high and brightness-low icons in the breeze set?
It looks like the icon theme you are using either:
- Has that icon but in black color and doesn’t follow the system/plasma colors
- It doesn’t have the icon and doesn’t set breeze as a falback
Also since you are using Panel Colorizer please make sure you’re using the latest version, if you are on plasma 6.3.4 there is a bug that causes coloring issues like that in your screenshot.
Icons in the plasma style are no longer used in Plasma 6, it uses only the icons from the icon theme now.
There’s a nextcloud.svg file in the darK-svg icon theme and it’s white, so for some reason the black glass Plasma theme I use is colouring it black. I downloaded the 2.6 version of the panel coloriser and neither mask nor effect are doing anything to re-colour the icon.
I just added nextcloud.svg to the breeze 48 set. So it has something to fall back on now.
Which icon theme are you using? Or more specifically, which icon theme does “black glass” theme specify?
The icon theme is DarK-svg (spelled that way) and according to the defaults of Black Glass, it was using an icon theme called Snowy though I have no such thing on my system and pointed it to DarK-svg, though that didn’t change anything.
The defaults file was located at /home/peter/.themes/org.magpie.blackglass.desktop/contents